diff --git a/src/Achievements/Achievements.ts b/src/Achievements/Achievements.ts
index 99db7d960..79edf12a9 100644
--- a/src/Achievements/Achievements.ts
+++ b/src/Achievements/Achievements.ts
@@ -1,4 +1,4 @@
-import { PlayerObject } from "src/PersonObjects/Player/PlayerObject";
+import { PlayerObject } from "../PersonObjects/Player/PlayerObject";
 import { AugmentationNames } from "../Augmentation/data/AugmentationNames";
 import { SkillNames } from "../Bladeburner/data/SkillNames";
 import { Skills } from "../Bladeburner/Skills";
@@ -341,7 +341,7 @@ export const achievements: Record<string, Achievement> = {
   SCRIPT_32GB: {
     ...achievementData["SCRIPT_32GB"],
     Icon: "bigcost",
-    Condition: () => Player.getHomeComputer().scripts.some((s) => s.ramUsage >= 32),
+    Condition: () => Player.getHomeComputer().scripts.some((s) => (s.ramUsage as number) >= 32),
   },
   FIRST_HACKNET_NODE: {
     ...achievementData["FIRST_HACKNET_NODE"],
diff --git a/src/Netscript/NetscriptHelpers.ts b/src/Netscript/NetscriptHelpers.ts
index 9f94fb3ed..d40b2cc08 100644
--- a/src/Netscript/NetscriptHelpers.ts
+++ b/src/Netscript/NetscriptHelpers.ts
@@ -33,6 +33,7 @@ import { BaseServer } from "../Server/BaseServer";
 import { dialogBoxCreate } from "../ui/React/DialogBox";
 import { checkEnum } from "../utils/helpers/enum";
 import { RamCostConstants } from "./RamCostGenerator";
+import { PositiveInteger } from "../types";
 
 export const helpers = {
   string,
@@ -158,12 +159,12 @@ function number(ctx: NetscriptContext, argName: string, v: unknown): number {
 }
 
 /** Convert provided value v for argument argName to a positive integer, throwing if it looks like something else. */
-function positiveInteger(ctx: NetscriptContext, argName: string, v: unknown): number {
+function positiveInteger(ctx: NetscriptContext, argName: string, v: unknown): PositiveInteger {
   const n = number(ctx, argName, v);
   if (n < 1 || !Number.isInteger(n)) {
     throw makeRuntimeErrorMsg(ctx, `${argName} should be a positive integer, was ${n}`, "TYPE");
   }
-  return n;
+  return n as PositiveInteger;
 }
 
 /** Returns args back if it is a ScriptArg[]. Throws an error if it is not. */
@@ -348,11 +349,6 @@ function updateDynamicRam(ctx: NetscriptContext, ramCost: number): void {
   if (ws.dynamicLoadedFns[fnName]) return;
   ws.dynamicLoadedFns[fnName] = true;
 
-  let threads = ws.scriptRef.threads;
-  if (typeof threads !== "number") {
-    console.warn(`WorkerScript detected NaN for thread count for ${ws.name} on ${ws.hostname}`);
-    threads = 1;
-  }
   ws.dynamicRamUsage = Math.min(ws.dynamicRamUsage + ramCost, RamCostConstants.Max);
   if (ws.dynamicRamUsage > 1.01 * ws.ramUsage) {
     log(ctx, () => "Insufficient static ram available.");
@@ -362,7 +358,7 @@ function updateDynamicRam(ctx: NetscriptContext, ramCost: number): void {
       `Dynamic RAM usage calculated to be greater than initial RAM usage.
       This is probably because you somehow circumvented the static RAM calculation.
 
-      Threads: ${threads}
+      Threads: ${ws.scriptRef.threads}
       Dynamic RAM Usage: ${formatRam(ws.dynamicRamUsage)} per thread
       Static RAM Usage: ${formatRam(ws.ramUsage)} per thread
 
diff --git a/src/Netscript/WorkerScript.ts b/src/Netscript/WorkerScript.ts
index 5687e0ced..0b2047fb2 100644
--- a/src/Netscript/WorkerScript.ts
+++ b/src/Netscript/WorkerScript.ts
@@ -72,7 +72,7 @@ export class WorkerScript {
   pid: number;
 
   /** Script's Static RAM usage. Equivalent to underlying script's RAM usage */
-  ramUsage = 0;
+  ramUsage = RamCostConstants.Base;
 
   /** Reference to underlying RunningScript object */
   scriptRef: RunningScript;
diff --git a/src/NetscriptFunctions.ts b/src/NetscriptFunctions.ts
index 68dafd904..0794f74ee 100644
--- a/src/NetscriptFunctions.ts
+++ b/src/NetscriptFunctions.ts
@@ -36,7 +36,7 @@ import {
 } from "./Server/ServerPurchases";
 import { Server } from "./Server/Server";
 import { influenceStockThroughServerGrow } from "./StockMarket/PlayerInfluencing";
-import { isValidFilePath, removeLeadingSlash } from "./Terminal/DirectoryHelpers";
+import { areFilesEqual, isValidFilePath, removeLeadingSlash } from "./Terminal/DirectoryHelpers";
 import { TextFile, getTextFile, createTextFile } from "./TextFile";
 import { runScriptFromScript } from "./NetscriptWorker";
 import { killWorkerScript } from "./Netscript/killWorkerScript";
@@ -890,7 +890,8 @@ export const ns: InternalAPI<NSFull> = {
             continue;
           }
           destScript.code = sourceScript.code;
-          destScript.ramUsage = sourceScript.ramUsage;
+          // Set ramUsage to null in order to force a recalculation prior to next run.
+          destScript.ramUsage = null;
           destScript.markUpdated();
           helpers.log(ctx, () => `WARNING: File '${file}' overwritten on '${destServer?.hostname}'`);
           continue;
@@ -899,11 +900,11 @@ export const ns: InternalAPI<NSFull> = {
         // Create new script if it does not already exist
         const newScript = new Script(file);
         newScript.code = sourceScript.code;
-        newScript.ramUsage = sourceScript.ramUsage;
+        // Set ramUsage to null in order to force a recalculation prior to next run.
+        newScript.ramUsage = null;
         newScript.server = destServer.hostname;
         destServer.scripts.push(newScript);
         helpers.log(ctx, () => `File '${file}' copied over to '${destServer?.hostname}'.`);
-        newScript.updateRamUsage(destServer.scripts);
       }
 
       return noFailures;
@@ -1430,12 +1431,14 @@ export const ns: InternalAPI<NSFull> = {
         let script = ctx.workerScript.getScriptOnServer(fn, server);
         if (script == null) {
           // Create a new script
-          script = new Script(fn, String(data), server.hostname, server.scripts);
+          script = new Script(fn, String(data), server.hostname);
           server.scripts.push(script);
-          return script.updateRamUsage(server.scripts);
+          return;
         }
         mode === "w" ? (script.code = String(data)) : (script.code += data);
-        return script.updateRamUsage(server.scripts);
+        // Set ram to null so a recalc is performed the next time ram usage is needed
+        script.ramUsage = null;
+        return;
       } else {
         // Write to text file
         if (!fn.endsWith(".txt")) throw helpers.makeRuntimeErrorMsg(ctx, `Invalid filename: ${fn}`);
@@ -1566,12 +1569,14 @@ export const ns: InternalAPI<NSFull> = {
       const scriptname = helpers.string(ctx, "scriptname", _scriptname);
       const hostname = helpers.string(ctx, "hostname", _hostname);
       const server = helpers.getServer(ctx, hostname);
-      for (let i = 0; i < server.scripts.length; ++i) {
-        if (server.scripts[i].filename == scriptname) {
-          return server.scripts[i].ramUsage;
-        }
+      const script = server.scripts.find((serverScript) => areFilesEqual(serverScript.filename, scriptname));
+      if (!script) return 0;
+      const ramUsage = script.getRamUsage(server.scripts);
+      if (!ramUsage) {
+        helpers.log(ctx, () => `Could not calculate ram usage for ${scriptname} on ${hostname}.`);
+        return 0;
       }
-      return 0;
+      return ramUsage;
     },
   getRunningScript:
     (ctx) =>
diff --git a/src/NetscriptFunctions/Extra.ts b/src/NetscriptFunctions/Extra.ts
index c5f8b0866..fe44f03f3 100644
--- a/src/NetscriptFunctions/Extra.ts
+++ b/src/NetscriptFunctions/Extra.ts
@@ -6,6 +6,7 @@ import { Apr1Events as devMenu } from "../ui/Apr1";
 import { InternalAPI } from "../Netscript/APIWrapper";
 import { helpers } from "../Netscript/NetscriptHelpers";
 import { Terminal } from "../Terminal";
+import { RamCostConstants } from "../Netscript/RamCostGenerator";
 
 export type INetscriptExtra = {
   heart: {
@@ -36,7 +37,7 @@ export function NetscriptExtra(): InternalAPI<INetscriptExtra> {
       real_document.completely_unused_field = undefined;
       // set one to true and check that it affected the other.
       real_document.completely_unused_field = true;
-      if (d.completely_unused_field && ctx.workerScript.ramUsage === 1.6) {
+      if (d.completely_unused_field && ctx.workerScript.ramUsage === RamCostConstants.Base) {
         Player.giveExploit(Exploit.Bypass);
       }
       d.completely_unused_field = undefined;
diff --git a/src/NetscriptFunctions/Singularity.ts b/src/NetscriptFunctions/Singularity.ts
index 1601a017f..c7fd32815 100644
--- a/src/NetscriptFunctions/Singularity.ts
+++ b/src/NetscriptFunctions/Singularity.ts
@@ -49,6 +49,7 @@ import { canGetBonus, onExport } from "../ExportBonus";
 import { saveObject } from "../SaveObject";
 import { calculateCrimeWorkStats } from "../Work/Formulas";
 import { findEnumMember } from "../utils/helpers/enum";
+import { areFilesEqual } from "../Terminal/DirectoryHelpers";
 
 export function NetscriptSingularity(): InternalAPI<ISingularity> {
   const getAugmentation = function (ctx: NetscriptContext, name: string): Augmentation {
@@ -77,18 +78,17 @@ export function NetscriptSingularity(): InternalAPI<ISingularity> {
     //Run a script after reset
     if (!cbScript) return;
     const home = Player.getHomeComputer();
-    for (const script of home.scripts) {
-      if (script.filename === cbScript) {
-        const ramUsage = script.ramUsage;
-        const ramAvailable = home.maxRam - home.ramUsed;
-        if (ramUsage > ramAvailable + 0.001) {
-          return; // Not enough RAM
-        }
-        const runningScriptObj = new RunningScript(script, []); // No args
-        runningScriptObj.threads = 1; // Only 1 thread
-        startWorkerScript(runningScriptObj, home);
-      }
+    const script = home.scripts.find((serverScript) => areFilesEqual(serverScript.filename, cbScript));
+    if (!script) return;
+    const ramUsage = script.getRamUsage(home.scripts);
+    if (!ramUsage) {
+      return Terminal.error(`Attempted to launch ${cbScript} after reset but could not calculate ram usage.`);
     }
+    const ramAvailable = home.maxRam - home.ramUsed;
+    if (ramUsage > ramAvailable + 0.001) return;
+    // Start script with no args and 1 thread (default).
+    const runningScriptObj = new RunningScript(script, ramUsage, []);
+    startWorkerScript(runningScriptObj, home);
   };
 
   const singularityAPI: InternalAPI<ISingularity> = {
diff --git a/src/NetscriptJSEvaluator.ts b/src/NetscriptJSEvaluator.ts
index dc43556d3..83e5e6a84 100644
--- a/src/NetscriptJSEvaluator.ts
+++ b/src/NetscriptJSEvaluator.ts
@@ -28,7 +28,6 @@ export async function compile(script: Script, scripts: Script[]): Promise<Script
   //If multiple compiles were called on the same script before a compilation could be completed this ensures only one compilation is actually performed.
   if (!script.queueCompile) return script.module as Promise<ScriptModule>;
   script.queueCompile = false;
-  script.updateRamUsage(scripts);
   const uurls = _getScriptUrls(script, scripts, []);
   const url = uurls[uurls.length - 1].url;
   if (script.url && script.url !== url) URL.revokeObjectURL(script.url);
diff --git a/src/NetscriptPort.ts b/src/NetscriptPort.ts
index 65573d53d..f2975ca38 100644
--- a/src/NetscriptPort.ts
+++ b/src/NetscriptPort.ts
@@ -1,12 +1,13 @@
 import { Settings } from "./Settings/Settings";
 import { NetscriptPort } from "@nsdefs";
 import { NetscriptPorts } from "./NetscriptWorker";
+import { PositiveInteger } from "./types";
 
 type PortData = string | number;
 type Resolver = () => void;
 const emptyPortData = "NULL PORT DATA";
 /** The object property is for typechecking and is not present at runtime */
-export type PortNumber = number & { __PortNumber: true };
+export type PortNumber = PositiveInteger & { __PortNumber: true };
 
 /** Gets the numbered port, initializing it if it doesn't already exist.
  * Only using for functions that write data/resolvers. Use NetscriptPorts.get(n) for */
diff --git a/src/NetscriptWorker.ts b/src/NetscriptWorker.ts
index c6d8f602a..9bba386f1 100644
--- a/src/NetscriptWorker.ts
+++ b/src/NetscriptWorker.ts
@@ -15,7 +15,6 @@ import { NetscriptFunctions } from "./NetscriptFunctions";
 import { compile, Node } from "./NetscriptJSEvaluator";
 import { Port, PortNumber } from "./NetscriptPort";
 import { RunningScript } from "./Script/RunningScript";
-import { getRamUsageFromRunningScript } from "./Script/RunningScriptHelpers";
 import { scriptCalculateOfflineProduction } from "./Script/ScriptHelpers";
 import { Script } from "./Script/Script";
 import { GetAllServers } from "./Server/AllServers";
@@ -32,8 +31,9 @@ import { parse } from "acorn";
 import { simple as walksimple } from "acorn-walk";
 import { areFilesEqual } from "./Terminal/DirectoryHelpers";
 import { Terminal } from "./Terminal";
-import { ScriptArg } from "./Netscript/ScriptArg";
+import { ScriptArg } from "@nsdefs";
 import { handleUnknownError } from "./Netscript/NetscriptHelpers";
+import { PositiveInteger } from "./types";
 
 export const NetscriptPorts: Map<PortNumber, Port> = new Map();
 
@@ -53,6 +53,7 @@ async function startNetscript2Script(workerScript: WorkerScript): Promise<void>
   const scripts = workerScript.getServer().scripts;
   const script = workerScript.getScript();
   if (script === null) throw "workerScript had no associated script. This is a bug.";
+  if (!script.ramUsage) throw "Attempting to start a script with no calculated ram cost. This is a bug.";
   const loadedModule = await compile(script, scripts);
   workerScript.ramUsage = script.ramUsage;
   const ns = workerScript.env.vars;
@@ -294,15 +295,7 @@ export function startWorkerScript(runningScript: RunningScript, server: BaseServ
  * returns {boolean} indicating whether or not the workerScript was successfully added
  */
 function createAndAddWorkerScript(runningScriptObj: RunningScript, server: BaseServer, parent?: WorkerScript): boolean {
-  // Update server's ram usage
-  let threads = 1;
-  if (runningScriptObj.threads && !isNaN(runningScriptObj.threads)) {
-    threads = runningScriptObj.threads;
-  } else {
-    runningScriptObj.threads = 1;
-  }
-  const oneRamUsage = getRamUsageFromRunningScript(runningScriptObj);
-  const ramUsage = roundToTwo(oneRamUsage * threads);
+  const ramUsage = roundToTwo(runningScriptObj.ramUsage * runningScriptObj.threads);
   const ramAvailable = server.maxRam - server.ramUsed;
   if (ramUsage > ramAvailable + 0.001) {
     dialogBoxCreate(
@@ -327,7 +320,7 @@ function createAndAddWorkerScript(runningScriptObj: RunningScript, server: BaseS
   // Create the WorkerScript. NOTE: WorkerScript ctor will set the underlying
   // RunningScript's PID as well
   const workerScript = new WorkerScript(runningScriptObj, pid, NetscriptFunctions);
-  workerScript.ramUsage = oneRamUsage;
+  workerScript.ramUsage = runningScriptObj.ramUsage;
 
   // Add the WorkerScript to the global pool
   workerScripts.set(pid, workerScript);
@@ -405,82 +398,61 @@ export function loadAllRunningScripts(): void {
 /** Run a script from inside another script (run(), exec(), spawn(), etc.) */
 export function runScriptFromScript(
   caller: string,
-  server: BaseServer,
+  host: BaseServer,
   scriptname: string,
   args: ScriptArg[],
   workerScript: WorkerScript,
-  threads = 1,
+  threads = 1 as PositiveInteger,
 ): number {
-  // Sanitize arguments
-  if (!(workerScript instanceof WorkerScript)) {
+  /* Very inefficient, TODO change data structures so that finding script & checking if it's already running does
+   * not require iterating through all scripts and comparing names/args. This is a big part of slowdown when
+   * running a large number of scripts. */
+
+  // Find the script, fail if it doesn't exist.
+  const script = host.scripts.find((serverScript) => areFilesEqual(serverScript.filename, scriptname));
+  if (!script) {
+    workerScript.log(caller, () => `Could not find script '${scriptname}' on '${host.hostname}'`);
     return 0;
   }
 
-  if (typeof scriptname !== "string" || !Array.isArray(args)) {
-    workerScript.log(caller, () => `Invalid arguments: scriptname='${scriptname} args='${args}'`);
-    console.error(`runScriptFromScript() failed due to invalid arguments`);
+  // Check if script is already running on server and fail if it is.
+  if (host.getRunningScript(scriptname, args)) {
+    workerScript.log(caller, () => `'${scriptname}' is already running on '${host.hostname}'`);
     return 0;
   }
 
-  args.forEach((arg, i) => {
-    if (typeof arg !== "string" && typeof arg !== "number" && typeof arg !== "boolean")
-      throw new Error(
-        "Only strings, numbers, and booleans can be passed as arguments to other scripts.\n" +
-          `${scriptname} argument index ${i} is of type ${typeof arg} and value ${JSON.stringify(arg)}`,
-      );
-  });
-
-  // Check if the script is already running
-  const runningScriptObj = server.getRunningScript(scriptname, args);
-  if (runningScriptObj != null) {
-    workerScript.log(caller, () => `'${scriptname}' is already running on '${server.hostname}'`);
+  const singleRamUsage = script.getRamUsage(host.scripts);
+  if (!singleRamUsage) {
+    workerScript.log(caller, () => `Ram usage could not be calculated for ${scriptname}`);
     return 0;
   }
 
-  // 'null/undefined' arguments are not allowed
-  for (let i = 0; i < args.length; ++i) {
-    if (args[i] == null) {
-      workerScript.log(caller, () => "Cannot execute a script with null/undefined as an argument");
-      return 0;
-    }
+  // Check if admin rights on host, fail if not.
+  if (host.hasAdminRights == false) {
+    workerScript.log(caller, () => `You do not have root access on '${host.hostname}'`);
+    return 0;
   }
 
-  // Check if the script exists and if it does run it
-  for (let i = 0; i < server.scripts.length; ++i) {
-    if (!areFilesEqual(server.scripts[i].filename, scriptname)) continue;
-    // Check for admin rights and that there is enough RAM available to run
-    const script = server.scripts[i];
-    let ramUsage = script.ramUsage;
-    threads = Math.floor(Number(threads));
-    if (threads === 0) {
-      return 0;
-    }
-    ramUsage = ramUsage * threads;
-    const ramAvailable = server.maxRam - server.ramUsed;
+  // Calculate ram usage including thread count
+  const ramUsage = singleRamUsage * threads;
 
-    if (server.hasAdminRights == false) {
-      workerScript.log(caller, () => `You do not have root access on '${server.hostname}'`);
-      return 0;
-    } else if (ramUsage > ramAvailable + 0.001) {
-      workerScript.log(
-        caller,
-        () =>
-          `Cannot run script '${scriptname}' (t=${threads}) on '${server.hostname}' because there is not enough available RAM!`,
-      );
-      return 0;
-    }
-    // Able to run script
+  // Check if there is enough ram to run the script, fail if not.
+  const ramAvailable = host.maxRam - host.ramUsed;
+  if (ramUsage > ramAvailable + 0.001) {
     workerScript.log(
       caller,
-      () => `'${scriptname}' on '${server.hostname}' with ${threads} threads and args: ${arrayToString(args)}.`,
+      () =>
+        `Cannot run script '${scriptname}' (t=${threads}) on '${host.hostname}' because there is not enough available RAM!`,
     );
-    const runningScriptObj = new RunningScript(script, args);
-    runningScriptObj.threads = threads;
-    runningScriptObj.server = server.hostname;
-
-    return startWorkerScript(runningScriptObj, server, workerScript);
+    return 0;
   }
+  // Able to run script
+  workerScript.log(
+    caller,
+    () => `'${scriptname}' on '${host.hostname}' with ${threads} threads and args: ${arrayToString(args)}.`,
+  );
+  const runningScriptObj = new RunningScript(script, singleRamUsage, args);
+  runningScriptObj.threads = threads;
 
-  workerScript.log(caller, () => `Could not find script '${scriptname}' on '${server.hostname}'`);
-  return 0;
+  return startWorkerScript(runningScriptObj, host, workerScript);
 }
diff --git a/src/RemoteFileAPI/MessageHandlers.ts b/src/RemoteFileAPI/MessageHandlers.ts
index d527d0198..39740ec96 100644
--- a/src/RemoteFileAPI/MessageHandlers.ts
+++ b/src/RemoteFileAPI/MessageHandlers.ts
@@ -124,8 +124,8 @@ export const RFARequestHandler: Record<string, (message: RFAMessage) => void | R
     if (!isScriptFilename(fileData.filename)) return error("Filename isn't a script filename", msg);
     const script = server.getScript(fileData.filename);
     if (!script) return error("File doesn't exist", msg);
-    const ramUsage = script.ramUsage;
-
+    const ramUsage = script.getRamUsage(server.scripts);
+    if (!ramUsage) return error("Ram cost could not be calculated", msg);
     return new RFAMessage({ result: ramUsage, id: msg.id });
   },
 
diff --git a/src/Script/RunningScript.ts b/src/Script/RunningScript.ts
index 02156d06b..ad6e3a672 100644
--- a/src/Script/RunningScript.ts
+++ b/src/Script/RunningScript.ts
@@ -10,7 +10,9 @@ import { Terminal } from "../Terminal";
 
 import { Generic_fromJSON, Generic_toJSON, IReviverValue, Reviver } from "../utils/JSONReviver";
 import { formatTime } from "../utils/helpers/formatTime";
-import { ScriptArg } from "../Netscript/ScriptArg";
+import { ScriptArg } from "@nsdefs";
+import { RamCostConstants } from "../Netscript/RamCostGenerator";
+import { PositiveInteger } from "../types";
 
 export class RunningScript {
   // Script arguments
@@ -52,25 +54,24 @@ export class RunningScript {
   pid = -1;
 
   // How much RAM this script uses for ONE thread
-  ramUsage = 0;
+  ramUsage = RamCostConstants.Base;
 
   // hostname of the server on which this script is running
   server = "";
 
   // Number of threads that this script is running with
-  threads = 1;
+  threads = 1 as PositiveInteger;
 
   // Script urls for the current running script for translating urls back to file names in errors
   dependencies: ScriptUrl[] = [];
 
-  constructor(script: Script | null = null, args: ScriptArg[] = []) {
-    if (script == null) {
-      return;
-    }
+  constructor(script?: Script, ramUsage?: number, args: ScriptArg[] = []) {
+    if (!script) return;
+    if (!ramUsage) throw new Error("Must provide a ramUsage for RunningScript initialization.");
     this.filename = script.filename;
     this.args = args;
     this.server = script.server;
-    this.ramUsage = script.ramUsage;
+    this.ramUsage = ramUsage;
     this.dependencies = script.dependencies;
   }
 
diff --git a/src/Script/RunningScriptHelpers.ts b/src/Script/RunningScriptHelpers.ts
deleted file mode 100644
index 54f6eebfc..000000000
--- a/src/Script/RunningScriptHelpers.ts
+++ /dev/null
@@ -1,22 +0,0 @@
-import { GetServer } from "../Server/AllServers";
-import { RunningScript } from "./RunningScript";
-
-export function getRamUsageFromRunningScript(script: RunningScript): number {
-  if (script.ramUsage != null && script.ramUsage > 0) {
-    return script.ramUsage; // Use cached value
-  }
-
-  const server = GetServer(script.server);
-  if (server == null) {
-    return 0;
-  }
-  for (let i = 0; i < server.scripts.length; ++i) {
-    if (server.scripts[i].filename === script.filename) {
-      // Cache the ram usage for the next call
-      script.ramUsage = server.scripts[i].ramUsage;
-      return script.ramUsage;
-    }
-  }
-
-  return 0;
-}
diff --git a/src/Script/Script.ts b/src/Script/Script.ts
index f4940c01b..3171f6589 100644
--- a/src/Script/Script.ts
+++ b/src/Script/Script.ts
@@ -10,6 +10,7 @@ import { ScriptUrl } from "./ScriptUrl";
 import { Generic_fromJSON, Generic_toJSON, IReviverValue, Reviver } from "../utils/JSONReviver";
 import { roundToTwo } from "../utils/helpers/roundToTwo";
 import { ScriptModule } from "./ScriptModule";
+import { RamCostConstants } from "../Netscript/RamCostGenerator";
 
 let globalModuleSequenceNumber = 0;
 
@@ -41,8 +42,8 @@ export class Script {
   dependencies: ScriptUrl[] = [];
   dependents: ScriptReference[] = [];
 
-  // Amount of RAM this Script requires to run
-  ramUsage = 0;
+  // Amount of RAM this Script requires to run. null indicates an error in calculating ram.
+  ramUsage: number | null = null;
   ramUsageEntries?: RamUsageEntry[];
 
   // Used to deconflict multiple simultaneous compilations.
@@ -51,14 +52,11 @@ export class Script {
   // hostname of server that this script is on.
   server = "";
 
-  constructor(fn = "", code = "", server = "", otherScripts: Script[] = []) {
+  constructor(fn = "", code = "", server = "") {
     this.filename = fn;
     this.code = code;
     this.server = server; // hostname of server this script is on
     this.moduleSequenceNumber = ++globalModuleSequenceNumber;
-    if (this.code !== "") {
-      this.updateRamUsage(otherScripts);
-    }
   }
 
   /** Download the script as a file */
@@ -97,14 +95,24 @@ export class Script {
 
     this.filename = filename;
     this.server = hostname;
-    this.updateRamUsage(otherScripts);
+    // Null ramUsage forces a recalc next time ramUsage is needed
+    this.ramUsage = null;
     this.markUpdated();
-    for (const dependent of this.dependents) {
-      const [dependentScript] = otherScripts.filter(
-        (s) => s.filename === dependent.filename && s.server == dependent.server,
+    this.dependents.forEach((dependent) => {
+      const scriptToUpdate = otherScripts.find(
+        (otherScript) => otherScript.filename === dependent.filename && otherScript.server === dependent.server,
       );
-      dependentScript?.markUpdated();
-    }
+      if (!scriptToUpdate) return;
+      scriptToUpdate.ramUsage = null;
+      scriptToUpdate.markUpdated();
+    });
+  }
+
+  /** Gets the ram usage, while also attempting to update it if it's currently null */
+  getRamUsage(otherScripts: Script[]): number | null {
+    if (this.ramUsage) return this.ramUsage;
+    this.updateRamUsage(otherScripts);
+    return this.ramUsage;
   }
 
   /**
@@ -112,11 +120,11 @@ export class Script {
    * @param {Script[]} otherScripts - Other scripts on the server. Used to process imports
    */
   updateRamUsage(otherScripts: Script[]): void {
-    const res = calculateRamUsage(this.code, otherScripts);
-    if (res.cost > 0) {
-      this.ramUsage = roundToTwo(res.cost);
-      this.ramUsageEntries = res.entries;
-    }
+    const ramCalc = calculateRamUsage(this.code, otherScripts);
+    if (ramCalc.cost >= RamCostConstants.Base) {
+      this.ramUsage = roundToTwo(ramCalc.cost);
+      this.ramUsageEntries = ramCalc.entries;
+    } else this.ramUsage = null;
     this.markUpdated();
   }
 
diff --git a/src/Server/BaseServer.ts b/src/Server/BaseServer.ts
index 0a4434f00..8abd21ea9 100644
--- a/src/Server/BaseServer.ts
+++ b/src/Server/BaseServer.ts
@@ -272,7 +272,8 @@ export abstract class BaseServer {
       if (fn === this.scripts[i].filename) {
         const script = this.scripts[i];
         script.code = code;
-        script.updateRamUsage(this.scripts);
+        // Set ramUsage to null in order to force recalculation on next run
+        script.ramUsage = null;
         script.markUpdated();
         ret.overwritten = true;
         ret.success = true;
@@ -281,7 +282,7 @@ export abstract class BaseServer {
     }
 
     // Otherwise, create a new script
-    const newScript = new Script(fn, code, this.hostname, this.scripts);
+    const newScript = new Script(fn, code, this.hostname);
     this.scripts.push(newScript);
     ret.success = true;
     return ret;
diff --git a/src/Server/ServerHelpers.ts b/src/Server/ServerHelpers.ts
index d15f84d7d..2ebd78a28 100644
--- a/src/Server/ServerHelpers.ts
+++ b/src/Server/ServerHelpers.ts
@@ -254,9 +254,9 @@ export function prestigeHomeComputer(homeComp: Server): void {
     homeComp.programs.push(Programs.BitFlume.name);
   }
 
-  //Update RAM usage on all scripts
+  //Reset RAM usage calculation for all scripts
   homeComp.scripts.forEach(function (script) {
-    script.updateRamUsage(homeComp.scripts);
+    script.ramUsage = null;
   });
 
   homeComp.messages.length = 0; //Remove .lit and .msg files
diff --git a/src/Terminal/commands/mem.ts b/src/Terminal/commands/mem.ts
index 994361d2b..423b7f29d 100644
--- a/src/Terminal/commands/mem.ts
+++ b/src/Terminal/commands/mem.ts
@@ -1,8 +1,9 @@
 import { Terminal } from "../../Terminal";
 import { formatRam } from "../../ui/formatNumber";
 import { Settings } from "../../Settings/Settings";
+import { BaseServer } from "../../Server/BaseServer";
 
-export function mem(args: (string | number | boolean)[]): void {
+export function mem(args: (string | number | boolean)[], server: BaseServer): void {
   try {
     if (args.length !== 1 && args.length !== 3) {
       Terminal.error("Incorrect usage of mem command. usage: mem [scriptname] [-t] [number threads]");
@@ -25,7 +26,10 @@ export function mem(args: (string | number | boolean)[]): void {
       return;
     }
 
-    const ramUsage = script.ramUsage * numThreads;
+    const singleRamUsage = script.getRamUsage(server.scripts);
+    if (!singleRamUsage) return Terminal.error(`Could not calculate ram usage for ${scriptName}`);
+
+    const ramUsage = singleRamUsage * numThreads;
 
     Terminal.print(`This script requires ${formatRam(ramUsage)} of RAM to run for ${numThreads} thread(s)`);
 
diff --git a/src/Terminal/commands/runScript.ts b/src/Terminal/commands/runScript.ts
index 86d04b8a3..00f820ca3 100644
--- a/src/Terminal/commands/runScript.ts
+++ b/src/Terminal/commands/runScript.ts
@@ -6,6 +6,8 @@ import { RunningScript } from "../../Script/RunningScript";
 import { findRunningScript } from "../../Script/ScriptHelpers";
 import * as libarg from "arg";
 import { formatRam } from "../../ui/formatNumber";
+import { ScriptArg } from "@nsdefs";
+import { isPositiveInteger } from "../../types";
 
 export function runScript(commandArgs: (string | number | boolean)[], server: BaseServer): void {
   if (commandArgs.length < 1) {
@@ -24,11 +26,12 @@ export function runScript(commandArgs: (string | number | boolean)[], server: Ba
   });
   const tailFlag = flags["--tail"] === true;
   const numThreads = parseFloat(flags["-t"] ?? 1);
-  if (numThreads < 1 || !Number.isInteger(numThreads)) {
-    Terminal.error("Invalid number of threads specified. Number of threads must be an integer greater than 0");
-    return;
+  if (!isPositiveInteger(numThreads)) {
+    return Terminal.error("Invalid number of threads specified. Number of threads must be an integer greater than 0");
   }
-  const args = flags["_"];
+
+  // Todo: Switch out arg for something with typescript support
+  const args = flags["_"] as ScriptArg[];
 
   // Check if this script is already running
   if (findRunningScript(scriptName, args, server) != null) {
@@ -46,7 +49,9 @@ export function runScript(commandArgs: (string | number | boolean)[], server: Ba
     // Check for admin rights and that there is enough RAM available to run
     const script = server.scripts[i];
     script.server = server.hostname;
-    const ramUsage = script.ramUsage * numThreads;
+    const singleRamUsage = script.getRamUsage(server.scripts);
+    if (!singleRamUsage) return Terminal.error("Error while calculating ram usage for this script.");
+    const ramUsage = singleRamUsage * numThreads;
     const ramAvailable = server.maxRam - server.ramUsed;
 
     if (!server.hasAdminRights) {
@@ -64,7 +69,7 @@ export function runScript(commandArgs: (string | number | boolean)[], server: Ba
     }
 
     // Able to run script
-    const runningScript = new RunningScript(script, args);
+    const runningScript = new RunningScript(script, singleRamUsage, args);
     runningScript.threads = numThreads;
 
     const success = startWorkerScript(runningScript, server);
diff --git a/src/Terminal/commands/top.ts b/src/Terminal/commands/top.ts
index 815eb66b8..9975151f4 100644
--- a/src/Terminal/commands/top.ts
+++ b/src/Terminal/commands/top.ts
@@ -1,6 +1,5 @@
 import { Terminal } from "../../Terminal";
 import { BaseServer } from "../../Server/BaseServer";
-import { getRamUsageFromRunningScript } from "../../Script/RunningScriptHelpers";
 import { formatRam } from "../../ui/formatNumber";
 
 export function top(args: (string | number | boolean)[], server: BaseServer): void {
@@ -45,7 +44,7 @@ export function top(args: (string | number | boolean)[], server: BaseServer): vo
     const spacesThread = " ".repeat(numSpacesThread);
 
     // Calculate and transform RAM usage
-    const ramUsage = formatRam(getRamUsageFromRunningScript(script) * script.threads);
+    const ramUsage = formatRam(script.ramUsage * script.threads);
 
     const entry = [script.filename, spacesScript, script.pid, spacesPid, script.threads, spacesThread, ramUsage].join(
       "",
diff --git a/src/Work/WorkStats.ts b/src/Work/WorkStats.ts
index 59a6f3e25..90b78fde9 100644
--- a/src/Work/WorkStats.ts
+++ b/src/Work/WorkStats.ts
@@ -1,4 +1,4 @@
-import { Person } from "src/PersonObjects/Person";
+import { Person } from "../PersonObjects/Person";
 import { Player } from "@player";
 import { Multipliers } from "../PersonObjects/Multipliers";
 
diff --git a/src/types.ts b/src/types.ts
index 1ea113c97..549a1affa 100644
--- a/src/types.ts
+++ b/src/types.ts
@@ -1,3 +1,12 @@
+// The object properties on these numeric types are for typechecking only and do not exist at runtime. They're just a way to require a typechecking function.
+export type Integer = number & { __Integer: true };
+export type PositiveNumber = number & { __Positive: true };
+export type PositiveInteger = Integer & PositiveNumber;
+
+// Numeric typechecking functions
+export const isInteger = (n: unknown): n is Integer => Number.isInteger(n);
+export const isPositiveInteger = (n: unknown): n is PositiveInteger => isInteger(n) && n > 0;
+
 /** Status object for functions that return a boolean indicating success/failure
  * and an optional message */
 export interface IReturnStatus {
diff --git a/src/ui/React/LogBoxManager.tsx b/src/ui/React/LogBoxManager.tsx
index edb7d1232..e5f281b81 100644
--- a/src/ui/React/LogBoxManager.tsx
+++ b/src/ui/React/LogBoxManager.tsx
@@ -20,6 +20,8 @@ import { Settings } from "../../Settings/Settings";
 import { ANSIITypography } from "./ANSIITypography";
 import { ScriptArg } from "../../Netscript/ScriptArg";
 import { useRerender } from "./hooks";
+import { areFilesEqual } from "../../Terminal/DirectoryHelpers";
+import { dialogBoxCreate } from "./DialogBox";
 
 let layerCounter = 0;
 
@@ -220,7 +222,17 @@ function LogWindow(props: IProps): React.ReactElement {
     if (server === null) return;
     const s = findRunningScript(script.filename, script.args, server);
     if (s === null) {
-      script.ramUsage = 0;
+      const baseScript = server.scripts.find((serverScript) => areFilesEqual(serverScript.filename, script.filename));
+      if (!baseScript) {
+        return dialogBoxCreate(
+          `Could not launch script. The script ${script.filename} no longer exists on the server ${server.hostname}.`,
+        );
+      }
+      const ramUsage = baseScript.getRamUsage(server.scripts);
+      if (!ramUsage) {
+        return dialogBoxCreate(`Could not calculate ram usage for ${script.filename} on ${server.hostname}.`);
+      }
+      script.ramUsage = ramUsage;
       startWorkerScript(script, server);
     } else {
       setScript(s);
diff --git a/src/ui/React/StatsProgressBar.tsx b/src/ui/React/StatsProgressBar.tsx
index 727f156ee..96d99f7c7 100644
--- a/src/ui/React/StatsProgressBar.tsx
+++ b/src/ui/React/StatsProgressBar.tsx
@@ -2,7 +2,7 @@ import * as React from "react";
 import LinearProgress from "@mui/material/LinearProgress";
 import { TableCell, Tooltip, Typography } from "@mui/material";
 import { characterOverviewStyles } from "./CharacterOverview";
-import { ISkillProgress } from "src/PersonObjects/formulas/skill";
+import { ISkillProgress } from "../../PersonObjects/formulas/skill";
 import { formatExp } from "../formatNumber";
 
 interface IProgressProps {
diff --git a/test/jest/Netscript/RamCalculation.test.ts b/test/jest/Netscript/RamCalculation.test.ts
index 83cedcc6c..89a27c086 100644
--- a/test/jest/Netscript/RamCalculation.test.ts
+++ b/test/jest/Netscript/RamCalculation.test.ts
@@ -36,8 +36,11 @@ describe("Netscript RAM Calculation/Generation Tests", function () {
   /** Creates a RunningScript object which calculates static ram usage */
   function createRunningScript(code: string) {
     script.code = code;
-    script.updateRamUsage([]);
-    const runningScript = new RunningScript(script);
+    // Force ram calculation reset
+    script.ramUsage = null;
+    const ramUsage = script.getRamUsage([]);
+    if (!ramUsage) throw new Error("Ram usage should be defined.");
+    const runningScript = new RunningScript(script, ramUsage);
     return runningScript;
   }
 
diff --git a/test/jest/Netscript/RunScript.test.ts b/test/jest/Netscript/RunScript.test.ts
index 51b7f4dfc..72eac62d1 100644
--- a/test/jest/Netscript/RunScript.test.ts
+++ b/test/jest/Netscript/RunScript.test.ts
@@ -52,7 +52,7 @@ test.each([
     const alerted = new Promise((resolve) => {
       alertDelete = AlertEvents.subscribe((x) => resolve(x));
     });
-    server = new Server({ hostname: "home", hasAdminRights: true, maxRam: 8 });
+    server = new Server({ hostname: "home", adminRights: true, maxRam: 8 });
     AddToAllServers(server);
     for (const s of scripts) {
       expect(server.writeToScriptFile(s.name, s.code)).toEqual({ success: true, overwritten: false });
@@ -61,8 +61,8 @@ test.each([
     const script = server.scripts[server.scripts.length - 1];
     expect(script.filename).toEqual(scripts[scripts.length - 1].name);
 
-    const runningScript = new RunningScript(script);
-    runningScript.threads = 1;
+    const ramUsage = script.getRamUsage(server.scripts);
+    const runningScript = new RunningScript(script, ramUsage as number);
     expect(startWorkerScript(runningScript, server)).toBeGreaterThan(0);
     // We don't care about start, so subscribe after that. Await script death.
     const result = await Promise.race([