HIS ATI Radeon HD 6990 Review. The Benchmarks.
Test 1. – Crysis Warhead.
Single card vs. Single card.
Whereas the HD 5970 struggled to sustain a smooth framerate at 1920×1200 with 8xAA and to an even greater degree at 2560×1600, the 6990 glided effortlessly through every iteration, maintaining an average in excess of the magic 30 FPS and thus, confirming the huge benefit yielded by its additional memory. In fact, for all three runs at the higher resolution,the minimum frame rate posted by AMD’s monster matched the maximum delivered by the 580.
Crossfire vs. SLI
A fascinating result here. The Nvidia cards as ever, scale brilliantly at both resolutions when in TRI SLI, whilst a second 6990 seems to offer only a modest bonus at 1920×1200. The question is, are we encountering a classic case of CPU bottle necking or is ATI’s scaling curse still rearing its ugly head? The answer is almost certainly the former and there is no clearer evidence than the results the 6990s managed to produce at the higher resolution of 2560×1600. These demonstrate a very healthy increase in performance overall and furthermore, one that is progressively larger as we enable AA and AF.
Crysis Warhead - Dual HD 6990 vs. Triple GTX 580
Get the Flash Player to see this player.Performance Analysis.
The percentages make things crystal clear, at 1920×1200, three 580s give us a raw performance boost of 81% relative to a single card and scale with an efficiency of 60%. These figures are based on the 3 results we obtained for average FPS at the resolution in question. The 6990s give us only an 8% raw performance gain at the same resolution and a scaling efficiency of just 54%. Both configurations are evidently being hampered by the CPU.
By contrast, at 2560×1600, we see a huge raw performance gain of 153% for the 580s with a scaling effeciency of 85% and for the ATI cards, a 59% increase in raw performance and a vastly improved scaling efficiency of 79%, not quite as high as with the Nvidia cards but remember, the 6990s are dual GPU cards and this is still massively impressive, especially when considering how the 5970s struggled in the same benchmark.
Finally, in the bang for the buck department, the 6990 more than makes good by its 25% advantage target for single card performance and in fact achieves a lead of 57% at 1920×1200 and an incredible 72% at 2560×1600 which, if we then subtract the 25% required to justify its higher price, gives it a net price/performance gain of 32% at 1920×1200 and 47% at 2560×1600.
For SLI/Crossfire, the 580s did perform 6% better at 1920×1200 though this is still 14% short of the 20% needed to justify their higher price and at 2560×1600, they fell 8% behind the 6990s, meaning that a pair of 6990s give superior performance for the price at both resolutions, by 14% and 28% respectively.