This appears to be a issue that affects most Unity games I own on my Linux distro. I tried discussing this on reddit earlier[1], asking for help to confirm this. At this point I’m confident that it’s a bug in de default rendering settings, most likely related to VSync.
My laptop is a Lenovo t440s with a Geforce GT 730M, running Ubuntu 15.04 and using the NVIDIA binary driver version 346.59.
I have systematically tested all of my games, here are my findings:
Has this issue: Besiege (both x86 and x64 versions), Crest, Desktop Dungeons, Gravity Ghost, Out There, Kerbal Space Program (both x86 and x64 versions, but not at the start while loading the assets), TIS-100
Does not have this issue: Jazzpunk
Depends on the settings: Mousecraft.
Note that many of these games are not that demanding. For example, Desktop Dungeons is a turnbased sprite game with barely any in-game animations, and don’t even get me started on the irony of TIS-100.
Mousecraft uses a launcher when opening the game in which one can change rendering settings. If VSync is turned off, the game maximises the CPU. If it is turned on, it barely uses any CPU resources at all.
Looking through the ~/.config/unity3d/[developer]/[game]/Player.log files (I’ve attached Jazzpunk and Besiege as examples), I’ve found the following when checking for VSync specifically. All of my unity games mention:
Setting maxVSyncInterval to 4
The value does not seem to matter, although most have it at 4. A little while later they all either have:
Default vsync count 0
or
Default vsync count 1
Again, the value does not seem to matter. Some logs precede this with:
Compositing window manager detected - disabling vsync for performance
This includes all the well-behaved games (Jazzpunk, Mousecraft), but also some of the games maxing out a CPU core (Besiege).
[1] Reddit - Dive into anything
2262047–151346–Besiege Player.log.txt (12.1 KB)
2262047–151347–Jazzpunk Player.log.txt (14.1 KB)