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 bilinear
| Peak bilinear
|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.
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