User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:58.0) Gecko/20100101 Firefox/58.0 Build ID: 20171207170405 Steps to reproduce: Enable WebRender - gfx.webrender.blob-images: true - gfx.webrender.enabled: true - gfx.webrender.hit-test: true - image.mem.shared: true Goto the Speedometer benchmark: https://mozilla.github.io/arewefastyet-speedometer/2.0/ Actual results: The CPU usage is constantly at ~30% constantly exceeding the GPU usage which roughly stays at 5% with the occasional spike. Expected results: I expected the CPU usage to not be this high. This could be a non-issue, but as people kept saying WebRender will use the GPU more than it does now the GPU usage stays pretty low compared to the CPU. Specs: CPU: I7 6700HQ @ 2.6GHz, RAM: 16.0GB Single-Channel 2400Mhz, GPU: Intel HD Graphics 530 OS: Windows 10 Pro 1709

I noticed the same with Servo. The GPU usage stayed really low while the CPU usage was pretty high.

Can you still reproduce this?

Yes, the CPU usage is still roughly 27% while the GPU usage is around 5 - 8%.

What do you get with WebRender off?

Without WebRender it has between 15% and 30% CPU usage and between 0.5% and 3% GPU usage.

I'd like to point out though that I created this issue because I assumed WebRender would use the GPU more instead of the CPU causing the CPU usage to go down. What was actually shown was similar CPU usage AND more GPU usage. The whole assumption could be incorrect.

This doesn't seem to be bad enough to block release.