Memory test, corrected. 2 October 2026. Edge 154, Second Bookmark Bar 3.1.131, Bookmark Sidebar 2.5.7.

Method: the browser's own processes (msedge.exe) of a throwaway profile are summed (working set and private bytes, MB). Local fixed pages, one site per tab. Extension settings are written from the service worker, with no extension page opened. The browser is restarted before measuring, which is the state after install day. Median of 2 runs.

Overhead over no extension, after a browser restart (working set / private, MB):
tabs | Second Bookmark Bar | Bookmark Sidebar
1    | +153 / +92          | +208 / +145
3    | +185 / +110         | +268 / +188
10   | +294 / +166         | +352 / +197

Same method on the install session (before a restart), working set:
tabs | Second Bookmark Bar | Bookmark Sidebar
1    | +134                | +166
3    | +177                | +172
10   | +340                | +325

Per tab, extra memory in the browser:
Second Bookmark Bar: about +3.5 to 4 MB per tab for the bar frame in the extension process. Web page itself about +15.5 WS / +8 private.
Bookmark Sidebar: web page about +19 WS / +9.5 private.

Caveats: differences under about 30 MB are noise. On live news pages the same setup moved by 100 to 170 MB between runs. GPU process size alone moves by about 30 MB between runs.

Correction: my first run measured Second Bookmark Bar unfairly. The setup script opened its settings page about 10 seconds before measuring, which left about 60 MB in its extension process. The onboarding tab added about 10 MB, and the script counted its own PowerShell process. Those first-run numbers are not published and should not be used.