AMD Radeon Refresh - HD 7970 GHz Edition (Review, Pt 2)
Graphics Core Next: One Year Later
Behind the scenes, AMD has been working to develop new and improved rendering processes for the GCN architecture. The first of these is a new rendering process called Forward+ Rendering. The end result is a combination of Forward and Deferred rendering techniques, that leverages the benefits of both.
With AMD rumored to be supplying the GPU for at least one next-gen console (based on Southern Islands), I wonder if this new Forward+ will find a home there. Note the slide bullet point that says "works well on game consoles".
From an implementation perspective, AMD is turning this into features such as Global Illumination and Advanced Lighting - both of which are featured in Dirt Showdown.
Sniper Elite V2 is also making use of these new features by using DirectCompute to accelerate the calculations for Anti-Aliasing, High Def Ambient Occlusion and Depth of Field.
App Acceleration
AMD continues to push the general-purpose computing abilities of GCN, by leveraging the industry standard OpenCL platform to unlock to the massively parallel architecture of its GPU platform.
In the recent press conference (and in the accompanying press deck) AMD touts wins on four very popular programs: Handbrake, WinZip, GIMP and Photoshop CS6. I think it's cool that GPUs continue to be leveraged to help with non-gaming tasks. I think it's doubly cool that open source apps such as Handbrake and GIMP are leveraging an open source standard like OpenCL to accelerate performance.
Conclusions
The new card is faster and more efficient than the original spin of the Tahiti silicon. While the GHz Edition did show substantial gains in 1080p benchmarking, I still say that a 3GB card is overkill for a single screen (except possibly a 27" or 30" panel running at 2560px wide, but I don't have one of those to test with).
The gains in Eyefinity were a bit more modest, but a 5% increase in performance lines up nicely with a 4% increase in price. If you're already in the market for an HD 7970, there is no reason not to spend the extra $20 for the GHz Edition. On the flip side, if you weren't interested in the HD 7970 before, this update probably won't sway you. Hopefully this new silicon does give us insight into what AMD is planning for the dual-GPU HD 7990. I'd love to see that card be dual versions of the HD 7970, rather than the HD 7950 (as has been the case with previous generations). It will also be interesting to see what AMD's partners can do with custom designs based on the GHz Edition.
If you're wondering how the refresh stacks up against the GTX 680, AMD claims it stacks up nicely and retakes the performance crown. I can't tell you for certain, because even after recent repeated attempts NVIDIA still doesn't see fit to let us borrow a card. I'm sure Kyle at HardOCP will have put both cards up against each other at 2560x1600. However, the card and driver have only been in out to press for less than a week, and they may not have been able to get multi-monitor stats as well.