diff --git a/main.js b/main.js
index 7c7c938..3a22ca7 100644
--- a/main.js
+++ b/main.js
@@ -1,3 +1,5 @@
+process.env.UV_THREADPOOL_SIZE = process.env.UV_THREADPOOL_SIZE || '64';
+const { monitorEventLoopDelay } = require('perf_hooks');
 const { app, BrowserWindow, ipcMain, dialog, clipboard, nativeTheme, Tray, Menu } = require('electron');
 nativeTheme.themeSource = 'dark';
 const path = require('path');
@@ -25,6 +27,10 @@ const stats = require('./lib/stats');
 const { createCollectors } = require('./lib/diagnostics-collectors');
 const { createAgent } = require('./lib/diagnostics-agent');
 
+const _eventLoopDelay = monitorEventLoopDelay({ resolution: 10 });
+_eventLoopDelay.enable();
+let _eldLastLog = 0;
+
 let mainWindow;
 let _lastImportPath = null;
 let dropTargetWindow = null;
@@ -181,6 +187,21 @@ function logMarker(label, fields) {
   debugLog(`────── ${label}${extra} ──────`);
 }
 
+function _maybeLogEventLoopDelay(activeJobs) {
+  const now = Date.now();
+  if (now - _eldLastLog < 5000) return;
+  _eldLastLog = now;
+  try {
+    const ns = 1e6;
+    const mean = (_eventLoopDelay.mean / ns).toFixed(1);
+    const max = (_eventLoopDelay.max / ns).toFixed(1);
+    const p99 = (_eventLoopDelay.percentile(99) / ns).toFixed(1);
+    const stddev = (_eventLoopDelay.stddev / ns).toFixed(1);
+    logInfo('perf', `eventloop-delay active=${activeJobs} mean=${mean}ms p99=${p99}ms max=${max}ms stddev=${stddev}ms threadpool=${process.env.UV_THREADPOOL_SIZE}`);
+    _eventLoopDelay.reset();
+  } catch {}
+}
+
 // Dedicated account-rotation log so users can trace fallback decisions
 // without wading through general debug output. Writes to account-rotation.log
 // in the same directory as fileuploader.log (honors user's configured path).
@@ -1705,6 +1726,7 @@ ipcMain.handle('start-upload', (_event, payload) => {
       if (data.state === 'uploading' && data.activeJobs > 0) {
         const speedMb = ((Number(data.globalSpeedKbs) || 0) / 1024).toFixed(1);
         updateTrayTooltip(`Upload: ${data.activeJobs} aktiv - ${speedMb} MB/s`);
+        _maybeLogEventLoopDelay(data.activeJobs);
       } else {
         updateTrayTooltip('Multi-Hoster-Upload');
       }