On my machine, Compiz uses ~25% of all 8 cores when I use the computer.
When I don't use it (so it's idle), Compiz uses around 50%.
How do I make compiz not use so much CPU?

I've struggled with this problem for years and it's annoying. My computer is a monster, but compiz is crippling it, and it's loudest and hottest when it's idle. I can't believe there is anything in Ubuntu that requires that much work all the time and especially not during idle.

  • OS = Ubuntu 15.04 (wondering whether upgrading to 15.10 would help, but probably not?)
  • DE = I use and like Unity (please don't suggest alternatives)
  • CPU = Intel i7, 16GB RAM
  • lspci | grep VGA = AMD Radeon 5450 (source)
  • /usr/lib/nux/unity_support_test -p = Not software rendered: no (source)
  • About this computer = Gallium 0.4 on llvmpipe (LLVM 3.6, 128 bits)
  • I don't currently have AMD drivers installed; last time I battled the compiz monster, I had big trouble even getting an image on the monitor. I'll take this challenge again if I have to, to make this compiz problem go away. OTOH downloading AMD drivers and using Catalyst seems to be not recommended (example source).
  • ccsm = Sync to VBlank is not ticked, and Texture Filter is "Fast". (source)
  • ccsm = As an experiment, I've now enabled "Force full screen redraw (buffer swap) on repaint". (source)

Your problem is the About this computer = Gallium 0.4 on llvmpipe (LLVM 3.6, 128 bits) line - this indicates that the CPU is doing all of the graphics processing, and compiz takes a lot!

You can try the oibaf drivers, available on lanchpad, or look for a proprietary driver for your card.

this question has a good, although dated, response about installing AMD drivers.

I don't have experience with the Radeon drivers myself, but I have seen numerous comments about issues. All of the comments that I have seen have a common thread: The operator got the driver working and then did a major version upgrade (like 15.04 to 15.10) and found that something broke. Often, the upgrade documentation will state directly that disabling proprietary drivers is required.

To check if Ubuntu knows about proprietary drivers for your system, hit the meta key, and start the program 'Additional Drivers'

  • Thank you Charles; that was also my hunch as I wrote this question. May I ask on what basis you suggest "oibaf" drivers, as I've not come across this before? And by "proprietary" do you mean the built-in "fglrx" drivers, or those that must be downloaded from amd.com? – Torben Gundtofte-Bruun Nov 4 '15 at 22:05
  • I use the oibaf drivers with an intel graphcis system, works great - they are between the built-in drivers and the cutting-edge drivers in terms of performance. Proprietary: The maker of the card does not release the source code for the driver, so Ubuntu does not include them normally. Sometimes they work well, other times.... – Charles Green Nov 4 '15 at 22:07
  • "[this question]" seems to be missing a link, right? – Torben Gundtofte-Bruun Nov 4 '15 at 22:17
  • @TorbenGundtofte-Bruun sigh. Thanks for pointing that out! – Charles Green Nov 4 '15 at 22:20
  • @TorbenGundtofte-Bruun Updated answer.... – Charles Green Nov 4 '15 at 22:26

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