Man of Honour
I'm happy so long as you keep your 290X's on top. At some point i will move above stock settings, so when i do watch out...
There is no reason why you can not go top, all you need to do is overclock the CPU to the max and then get a reasonable run out of two cards.
The thing to watch out for is bottlenecking the GPUs as this puts a lot of stress on the CPU which in turn gives more crashes than the gameplay.