Originally Posted by Alatar
Compute isn't the reason AMD is inefficient this gen.
Titan has much higher FP32 and FP64 perf than a 1ghz Tahiti but only consumes about the same amount of power.
Tahiti was the first chip to release on TSMC 28nm. it must have taped out in late Q1 2011. it released on jan 9, 2012. AMD's design must have been very conservative as it was on a immature process. secondly HD 7970 Ghz is the same silicon with increased voltage and a different BIOS. HD 7970 Ghz loses efficiency as its voltage is increased to 1.25v from 1.175v on original HD 7970. the ref AMD HD 7970s easily overclocked to 1100 mhz at 1.175v and were more power efficient than HD 7970 Ghz.
Pitcairn (212 sq mm) performs very well on perf/watt and perf/ sq mm wrt its Kepler counterpart GK106 (214 sq mm). also with HD 7790 Bonaire AMD fit 30% extra perf within the same 85W TDP of HD 7770 . the newer power management allowed AMD to fit the 30% extra perf for just 37 sq mm extra die size. so Kepler is not an inherently more efficient architecture than GCN.
1920 x 1200 perf/watt
HD 7970 Ghz - 77
HD 7970 - 91
GTX 680 - 95
GTX 660 - 100
MSI GTX 650 Ti boost - 100
HD 7870 - 107
HD 7790 - 107
HD 7850 - 108
by increasing the front end to 4 ACE, 4 geometry engines, 4 raster engines and ROP to 48 AMD can extract better per sp performance. even with 2048 sp a 10% improvement is very much likely. add to it 25% more stream processors and some aggressive chip binning with core clocks of 1 Ghz at voltage of 1.175v - 1.2v and there is no doubt AMD can increase perf by 30% at same TDP for a die size of 450 sq mm. on a mature TSMC 28nm process that should not be a problem. moreover if Nvidia can get 7 billion transistor GK110 running at close to 1 ghz max boost within 250w tdp AMD can definitely fit a 5.5 billion transistor HD 9970 running at 1 ghzEdited by raghu78 - 7/21/13 at 8:46am