General Rendering Performance

General Shading

Using our shader rate tester (and including a quick go with an early in-house D3D10 tester to check the MUL rate), we can see that with ForceWare 158.14 under Vista x86 and x64, the second MUL ALU in each SP is still unavailable for general shading in G84. Observing that limitation and pushing other instruction combinations through the hardware shows G84 is as willing to run at near-peak throughput as G80 is, hinting that the current driver is quite happy working with 2 G8x clusters as it is 6, at least with our simple shaders design to test maximum rates.

ROP Rates

We observed Z-only rates of 28Gpixels/sec, pure pixel fillrate of 5.1Gpixel/sec (about 87% of peak at 730MHz) and an INT8 blend rate around half that at 2.5Gpixels/sec, indicating ROPs that are the same as G80 (and a bandwidth limit for the Z-only rate, just like on G80), using testers from Marco Dolenc and Victor Moya.

Filtering rates

We see filter rates ~7.2Gtexels/s using uncompressed INT8 RGBA textures and an in-house tester, indicating most likely a bandwidth limitation stopping performance approaching the 11.68Gtexels/sec peak theoretical rate. With trilinear filtering and compressed textures to minimize bandwidth concerns, filtering rates are much nearer to those claimed in the specification sheets, as expected.

We're remiss in not being able to spend enough time evaluating pure and application performance outside of video playback, so stay tuned while we fill the gaps. We're certain our friends at HEXUS, The Tech Report and Hardware.fr will cover those bases while we get round to it.