How do you turn off vsync for Source games?

[eydee]

I'm playing HL2 EP2 at the moment. Something I noticed is vsync being always on, which hurts performance a bit. I would also like to see what the radeon driver is capable of compared to fglrx, but the fps is capped at the refresh rate and won't go further.

While vblank_mode=0 works for a few things, e.g. glxgears, it has no effect on HL2. I tried starting Steam with "vblank_mode=0 steam" and also putting it into the launch options field for EP2. No matter what I do, vsync is on. Steam does notice in the terminal output, that vblank_mode is overriden by the environment, but the game doesn't care a bit.

Can I do anything to turn off vsync? Is there some other "magic" environment variable I should know about? (I'd prefer not reconfiguring the whole X for a single game, if possible.) The in-game setting for vsync is disabled the whole time, of course. I also tried the settings in ~/.drirc as well, it is also noted in the terminal output and being ignored.

Arch x64, kernel 3.17.4-1-ARCH
Radeon 6850

[marco26]

you need to go to advanced settings in the game menu and disable it.

[eydee]

you need to go to advanced settings in the game menu and disable it.

I did. No matter what it is set to, vsync is on.

[droste]

You probably have to add this to your xorg.conf Device section:

Section "Device"
    ...
    Option "SwapBuffersWait" "false"
    ...
EndSection

[dungeon]

Yeah for EXA "SwapBuffersWait" false is also needed sometimes, for glamor only vblank_mode=0 is enough