SGX545 vs AMD/Nvidia

PowerVR Insider
2

Hi,



SGX545 at 400 MHz has the following peak rates:



800 Mpixels/sec textured fillrate (2 textured pixels per clock)

6.4 Gflops (4 flops per clock per USSE, 4 USSEs total)

80 M transformed triangles/sec (5 clocks per triangle)



So the ROPs (SGX doesn’t really have the same implementation of the back end of the traditional GPU pipeline as the GPUs you’re trying to compare it to, but let’s call it a ROP for the sake of comparison) run at core clock, not half as you’ve speculated.



We’ve long marketed SGX using a 2.5x multiplier for fillrate, which takes our TBDR architecture into account and assumes an average per-pixel opaque overdraw of 2.5x, which gives you 2 Gpixels/sec, but that’s under the aforementioned assumptions which need a certain workload to become accurate.



As you’ve found out, it’s very difficult to compare those on-paper peaks to those of a traditional PC-based IMR like a GeForce or a Radeon, because the architectures and available resources for the GPUs are so completely different.



I wouldn’t like to guess at which PC GPU is closest in the real world to a 400 MHz GMA3600; only benchmarking can tell you that, doing it from on-paper stats is fraught with assumption and architectural understanding.



I hope that helps!



Rys