So we've learned from this review what was already apparent.
7970: Great for compute and has bandwidth to back abundant shaders. Those same shaders and bandwidth/buffer in comparison to ROPs hurts power efficiency in gaming, and size/power requirements hinder potential market. Since it has more-than-enough of everything (for it's ROPs) and enough tdp to max out the process, it can justify it's price through unique abilities (bigger buffer for high-rez, greater compute/dpfp for gpgpu, absolute performance) for those willing to take the size/energy trade-off.
680: Very smart chip for spfp/1080p, but the no-waste design hurts yields and increases price given the state of 28nm during its (initial) lifespan.
670: 1344 (1568) Strictly shader/SFU limited versus 680...but better yields hence lower price. Slightly less optimal shader/rops and shader/bandwidth efficiency.
7950: 1792sp is an optimal design considering the ROP count (like 680) for gaming and smart choice for the mainstream performance part because it is using a salvage design on a new process; too much bandwidth/buffer hurts power efficiency/form factor but is a side-effect of 7970's strengths (even if niche). Clocks great because of high tdp and low-voltage binning.
660ti: 1344 (equivalent of 1568), efficient mix of rops, ram, bandwidth, and shaders and clockspeed potentials...hampered by overall units vs 7950 but better than 7870, tdp (clockspeed) and bandwidth limitations beyond ~1100mhz/7000 create a 'bottleneck' that actually fits with the design/market. It's a smart salvage chip considering the power consumption and clocks for ram on the smaller bus with less rops and the minimum clock to expect from the 28nm process (like an AMD xx50 part at default voltage).
7870: 1280sp. Efficient mix of bandwidth, shaders, ram, and clockspeed potentials. Clocks great and with great performance efficiency because of 170w tdp coupled with low-speed (but capable enough for the shaders at high clock) ram on a very small chip with a 256-bit bus. Hampered by lack of shaders vs. ROPs.
In essence...they all play different angles and show where each company is compounding their efforts and expectations. Judging purely on IPC/capabiities, 7950 is a great performance card. 660ti is a great gamer card. 7870 is a great point-of-entry for 1080p. Although I think the 660ti could shed $20 considering the price of the competition, it's smaller and more energy efficient. If you think purely in those terms...that's probably worth it. Some will like the over-all more robust potential of 7950 or the capabilities/$ of 7870. Not a bad choice in the bunch...but I still wait patiently for an AMD version of gk104 to drive prices down and performance/efficiency/form-factor/$ up.
Gotta feel sorry for you guys.
