Tips to improve performance

If the viewer is slow or stutters, it's almost always a browser memory problem. CBCTHub isn't slow on its own — it depends on how much RAM your browser has available to process the volume.

Before opening a heavy exam

1. 1
   Close all other browser tabs. Each tab uses RAM. If you have 20 open, there's little memory left for CBCTHub.
2. 2
   Close heavy apps: Photoshop, Premiere, virtual machines, programming IDEs. They free up a lot of RAM.
3. 3
   Restart the browser if you've been using it for hours. It accumulates memory without releasing it well after heavy use.
4. 4
   Check that the battery isn't in power-saving mode. Many laptops drop CPU performance on battery to save power.

While using the viewer

• Don't open 3D View if you don't need it. It's the heaviest view — uses full volume rendering. If you're just reviewing slices, stay in Orthogonal/Panoramic.
• Close panels you're not using (report panel, annotations panel) to free screen space and reduce rendering work.
• If comparing exams, make sure you have at least 16 GB of RAM — the comparator loads two volumes simultaneously.
• Use W/L sliders instead of Shift+drag to avoid constant re-renders during adjustment.

When the viewer starts slowing down

1. 1
   Reload the tab (Ctrl+R / Cmd+R). This frees accumulated memory.
2. 2
   If reloading isn't enough, close the tab and re-open the exam from My exams.
3. 3
   If still slow, restart the whole browser.
4. 4
   If nothing works, restart the computer. Accumulated RAM in system apps may affect it.

Hardware acceleration

Make sure your browser has hardware acceleration enabled. It makes a huge difference in 3D View and viewer transitions:

• Chrome: Settings → System → “Use hardware acceleration when available” → ON.
• Edge: Settings → System and performance → “Use hardware acceleration” → ON.
• Safari: always on in Mac, not configurable.
• Firefox: Settings → General → Performance → Check “Use hardware acceleration”.

Clear cache

If the viewer behaves oddly (slices not appearing, corrupted 3D model), clearing the cache may help:

• Chrome/Edge: Ctrl+Shift+Delete → just “Cookies and other site data” and “Cached images and files”.
• Safari: Safari → Clear history → Last hour.