Yes — but as I said, running the game in a Parallels Windows VM results in 2x better performance than running the same game natively. The same OSX graphics driver is used in both cases, except the VM has to do extra work! How does that make any sense?
A wild guess would be that OS X drivers contain poor shader optimizer.
Parallels probably work by decompiling DirectX shader bytecode back into GLSL, which is already optimized for OS X shader compiler, therefore there is less burden on the optimizer.
Not 100% sure, but I was under the impression that unlike Windows (?), OSX simply does not allow you to have direct hardware access. (Plus, if Parallels was accessing the hardware directly, how would you be able to run the VM in a window while still doing OSX stuff underneath?)
Either way, there's clearly a way to make the game run significantly faster on OSX, but Valve isn't doing it for some reason.
I can't speak to OSX, but on linux I know that virtualbox likes to install kernel modules into the host. If your VM does that, then it should be able to get direct hardware access.
