- regardless of graphics driver, on GNU/Linux it's much slower than on Windows. The Free (radeon) driver is a wreck on the R9 290(X) right now.
Though in general I wouldn't recommend looking at any AMD gpus right now, anyway - they are still all heavily above MSRP from the after effects of litecoin miners. They lose the price / performance context with every nvidia part even without considering how Linux drivers are worse for their stuff.
And I wouldn't expect retailers to drop prices until the demand goes away, and apparently it hasn't. I'd wait for Maxwell to force a price cut out of AMD before buying anything.