My reference watercooled 290X won't do above 1275MHz, even with 2v on the GPU... Should I throw it in the trash and get a GTX 780 Ti K|NGP|N? What can I do to allow high GPU clocks?
First off why do you want such high clocks?
Are you upping the RAM speed too?
I want SPEED!!! I have the RAMs at 1700MHz.
Its a pretty solid overclock. 1275mhz is probably just the limit of your 290x's silicon.
Okay back off the RAM. It may be holding the core clock back.
Leave the RAM stock and up the Core and when it goes unstable bump the voltage. Continue till Max stable core.
Now reset the core to stock and up the RAM till Max stable.
Once you have found Max each. Up them together in sensible amounts together. Till over all stability.
But if you want sheer speed. Up the core till stable, and then just up the RAM till the thing is unstable. The core is the important part the RAM will keep up and not impact too much if it is a little slower.