at present the 980 is the best GPU on market, but the added memory on the 290x is coming into the state of play these days for the newer game releases that are coming out, for an example look at the Dying Light game specs that is coming out
http://www.overclock3d.net/articles/gpu_displays/dying_light_pc_specs_released/1
MINIMUM:
OS: Windows® 7 64-bit / Windows® 8 64-bit / Windows® 8.1 64-bit
Processor: Intel® Core™ i5-2500 @3.3 GHz / AMD FX-8320 @3.5 GHz
Memory: 8 GB RAM DDR3
Hard Drive: 40 GB free space
Graphics: NVIDIA® GeForce® GTX 670 / AMD Radeon™ HD 7870
Sound: DirectX® 10
Now witness true horror in the form of the Dying Light “recommended” specs.
RECOMMENDED:
OS: Windows® 7 64-bit / Windows® 8 64-bit / Windows® 8.1 64-bit
Processor: Intel® Core™ i5-4670K @3.4 GHz / AMD FX-8350 @4.0 GHz
Memory: 16 GB RAM DDR3
Hard Drive: 40 GB free space
Graphics: NVIDIA® GeForce® GTX 780 / AMD Radeon™ R9 290
Sound: DirectX® 10
With the ports from the XBone and PS4, they are needing more and more GPU memory it seems with each incremental release. 3GB these days is seeming to be not enough, 4GB is capable of handling it, and anything more is not just over the top, it is becoming needed.