Single page Print

Texture filtering
We'll begin with a series of synthetic tests aimed at exposing the true, delivered throughput of the GPUs. In each instance, we've included a table with the relevant theoretical rates for each solution, for reference.

Peak pixel
fill rate
Peak bilinear
Peak bilinear
FP16 filtering
GeForce GTX 560 Ti 29 58 58 134
GeForce GTX 560 Ti 448 29 41 41 152
GeForce GTX 580 37 49 49 192
GeForce GTX 680 32 129 129 192
Radeon HD 5870 27 68 34 154
Radeon HD 6970 28 85 43 176
Radeon HD 7870 32 80 40 154
Radeon HD 7970 30 118 59 264

The pixel fill rate is, in theory, determined by the speed of the ROP hardware, but this test usually winds up being limited by memory bandwidth long before the ROPs run out of steam. That appears to be the case here. Somewhat surprisingly, the GTX 680 manages to match the Radeon HD 7970 almost exactly, even though the Radeon has substantially more potential memory bandwidth on tap.

Nvidia's new toy comes out looking very good in terms of texturing capacity, more than doubling the performance of the GeForce GTX 580 in the texture fill and integer filtering tests. Kepler's full-rate FP16 filtering allows it outperform the 7970 substantially in the final test. In no case does the GTX 680's relatively lower memory bandwidth appear to hinder its ability to keep up with the 7970.

Tessellation and geometry throughput

GeForce GTX 560 Ti 1800 134
GeForce GTX 560 Ti 448 2928 152
GeForce GTX 580 3088 192
GeForce GTX 680 4024 192
Radeon HD 5870 850 154
Radeon HD 6970 1780 176
Radeon HD 7870 2000 154
Radeon HD 7970 1850 264

Although the GTX 680 has a higher theoretical rasterization rate than the GTX 580, the GK104 GPU has only half as many setup and tessellator units (aka PolyMorph engines) as the GF110. Despite that fact, the GTX 680 achieves twice the tessellation performance of Fermi. The GTX 680 even exceeds that rate in TessMark's 64X expansion test, where it's nearly three times the speed of the Radeon HD 7970. We doubt we'll see a good use of a 64X geometry expansion factor in a game this year, but the Kepler architecture clearly has plenty of headroom here.