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Round 1: Running the numbers

Peak
pixel
fill rate
(Gpixels/s)
Peak bilinear
INT8 texel
filtering
rate
(Gtexels/s)
Peak bilinear
FP16 texel
filtering
rate
(Gtexels/s)
Peak
memory
bandwidth
(GB/s)
Peak shader
arithmetic (GFLOPS)
Single-
issue
Dual-
issue
GeForce 8800 GT 11.2 39.2 19.6 64.6 392 588
GeForce 9800 GTX 10.8 43.2 21.6 70.4 432 648
GeForce GTS 250 12.3 49.3 24.6 71.9 484 726
GeForce GTX 260 (216 SPs) 18.2 46.8 23.4 128.8 605 907
GeForce GTX 275 17.7 50.6 25.3 127.0 674 1011
GeForce GTX 285 21.4 53.6 26.8 166.4 744 1116
GeForce GTX 470 24.3 34.0 17.0 133.9 1089 -
GeForce GTX 480 33.6 42.0 21.0 177.4 1345 -
Radeon HD 3870 13.6 13.6 13.6 73.2 544 -
Radeon HD 4850 11.2 28.0 14.0 63.6 1120 -
Radeon HD 4870 12.0 30.0 15.0 115.2 1200 -
Radeon HD 4890 14.4 36.0 18.0 124.8 1440 -
Radeon HD 5750 11.2 25.2 12.6 73.6 1008 -
Radeon HD 5770 13.6 34.0 17.0 76.8 1360 -
Radeon HD 5830 12.8 44.8 22.4 128.0 1792 -
Radeon HD 5850 23.2 52.2 26.1 128.0 2088 -
Radeon HD 5870 27.2 68.0 34.0 153.6 2720 -

We've already looked at the GTX 480's theoretical capacities in some detail, but the table above gives us a wider view and includes the GeForce GTX 470, as well. These numbers are instructive and sometimes helpful for handicapping things, but delivered performance is what matters most, so we won't fixate on them too much. For instance, note how the GeForce GTX 470's basic specs compare to its likely chief rival, the Radeon HD 5850. The pixel fill rate and memory bandwidth of the two cards are comparable, with a slight edge to the GeForce in both categories. The 5850 has almost double the peak texturing and shader arithmetic rates, though. The balances here are very different in theory, but I doubt the real-world performance will diverge nearly that dramatically.

We can use some synthetic tests to give us a better sense of things. We're not especially enamored with 3DMark Vantage overall, but its directed benchmarks will have to do for now.

The results of this test tend to track pretty closely with theoretical memory bandwidth numbers, and the new GeForces appear to follow suit. That puts the GTX 480 at the top of the heap, with the GTX 470 settling in just below the Radeon HD 5850. Of course, ROP rates are crucial for things other than just raw pixel fill rates, most notably for antialiasing performance. We'll look at that aspect of things in the following pages.

We learned in the process of putting together our Radeon HD 5830 review that 3DMark's texture fill rate test really is just that and nothing more—textures aren't even sampled bilinearly. The test does employ FP16 texture formats, but the result is to put GeForce GTX 200-series GPUs (and older Nvidia parts) at a disadvantage, since they can only sample FP16 textures at the rate they filter them, while newer Radeons can sample FP16 textures at full speed. Fortunately, the GF100 can also sample FP16 formats at full speed, so it's not handicapped by the peculiarities of this test.

In fact, both GF100 cards prove to be quite efficient here, coming close to their projected peak rates. Then again, the Radeons look to be similarly efficient, with markedly higher peak throughput.

These directed shader tests have long been a study in contrasts, with the architectures from rival camps showing their relative strengths on different workloads. If anything, that contrast is heightened by the arrival of the GF100. The Radeons rule the Perlin noise and parallax occlusion mapping tests, while the new GeForces dominate the GPU cloth and particle simulations. If we can learn anything from these results, I'd say the lesson is that the Radeon HD 5870's gaudy advantage in peak FLOPS rate on paper doesn't necessarily translate into superior shader performance.