High CPU/GPU usage & fan running when using TZP in Firefox 33.0+ on Windows

[dadler]

Several users have reported high CPU or GPU usage when TZP shows a pop-up on certain images. Some users report this as TZP causing the fan to run fast or GPU "coil whine".

It seems to be related to Firefox's recent feature OMTC "off main thread compositing", which was enabled in 33 (at least on Windows).

The workaround is to OMTC off by setting this to false in the about:config firefox page:

• layers.offmainthreadcomposition.enabled

I've filed a bug report with Mozilla but they say they haven't had a chance to investigate yet: Bug 1089297 - High CPU or GPU usage with Thumbnail Zoom Plus & OMTC (offmainthreadcomposition) on Windows

One user also reported:

[Turning off layers.offmainthreadcomposition.enabled] did something, still going into 3D mode on certain reddit pictures, not sure which ones seems random. I think gifs don’t trigger the problem at all (with OMTC on). With OMTC off it doesn’t sound like its rendering at 1000+ fps either. I have a AMD 7850 btw.

Related support emails:

• "About the Thumbnail Zoom Plus" 2014-09-21 6:28 AM - zielinski...
• "FF 33.0 / TZP 3.1" 10/15/14 6:09 PM - thirteen_squared
  • Firefox 33.0; turning off layers.offmainthreadcomposition.enabled helped.
  • Reverting to ff 32 avoids the problem.
• "bug report -" 10/19/2014 8:29 PM - lukasz
  • Firefox Nightly 36.0a1 (2014-10-19)
  • Current GPU is a 7970 with one of the most recent Catalyst builds installed. Win8.1.
• "Coil whine when using add-on" 10-24-1024 12:14 PM - jtbell \ disabling [layers.offmainthreadcomposition.enabled] actually did make the coil whine stop on Firefox 33/Windows 7 64.
• "possible bug?" 10/14/14 5:08 PM wolfies...
  • not sure if this is the same problem (reported as a hang).

[dadler]

I've filed a bug against Firefox: Bug 1089297 - High CPU or GPU usage with Thumbnail Zoom Plus & OMTC (offmainthreadcomposition) on Windows

[dadler]

For repro steps see my entry in comment 11 of the Bugzilla bug report. Thanks to user pls... for emailing me the clue which unlocked the achievement!

The problem appears to happen only when the pop-up is overlapped by the Windows task bar in always-on-top mode (at least in my testing). Positioning the Firefox window differently so they don't overlap may work around the problem.

[Seagulls]

Just to comment on this, setting layers.offmainthreadcomposition.enabled to false has stopped the coil whine - using ff 33 windows 7 x64