EDIT2:
Turns out the Mac version is not even build 30... So I guess the rest of the post is moot.

It's been a while since I tried this game on a Mac. The game runs smooth when windowed, but as soon as I go fullscreen, even the main menu slows down to about 15 fps and I get screen tearing as well.
Is this a known problem? I'm using Mavericks on a Core 2 Duo iMac.

Things I've tried:
- Disabling steam overlay.
- Playing without Steam (instant crash).
- Fiddling with system accessibility options.
- Changing resolutions / windowed modes.

Is this a known problem? Are there any known solutions?

EDIT:
On a possibly unrelated note, my workshop subscriptions are not downloading (again, on Mac).

I have the same issue on my Macbook air 2013 i7 model. It's a known issue and i hope it's been fixed for build 30 but only time will tell. Hopefully we won't have to wait that long

I'm reviving this thead

I have been testing B30 and i still experience performance problems, although my fps says constantly 500...
I don't think this will ever be fixed, i might be a problem laying deep down in the engine.