The title says it all. It varies though as WoW is running when it will go to sleep mode could be 5 min, could be hours. I've no idea why it does this.

I've done all these:
Reset SMC
My energy saver is set to not shut down and hot corners are off.
Not overheating.
I've reinstalled WoW.

It's been to a mac registered repair shop 2 times now and they couldn't find anything but to check the settings. So they've done nothing of help but cost me 44$ 2nd trip was free though.

So I've come to the community here for help. I'm now clueless to what could be the problem causing this.