SDRAM vs. RDRAM, Facts and Fantasy

Id Software Quake III Arena

Inspecting at the Quake III Arena benchmarks, we can clearly see that at 1024x768 the GeForce DDR is fill-rate limited, as all motherboards are in the 50 FPS range. In the 640x480 resolution, however, we can see quite a few differences. What is actually suprising to see is that the VIA 694X Apollo Pro 133A chipset has the highest scores in the 800 MHz benchmarks, but the Intel i820 has the highest scores at 600 MHz. This would indicate that the Intel i820 chipset has less CPU overhead than the other chipsets, which should have shown up in the 800 MHz scores, too, but doesn’t. Also note the 1024x768 scores for the Intel i820 chipset; if there was less CPU overhead these would have been much higher, as the i820 now is consistently last in that resolution, at any clockspeed.

If we however take memory throughput into consideration, it is strange that a chipset with the lowest memory throughput of all, the VIA 694X Apollo Pro 133A, would best the two others. The Intel 440BX chipset is obviously operating at AGP 2X as it has no support for AGP 4X, but we’d expected better from the i820’s AGP 4X implementation. By the looks of it, VIA’s AGP 4X implementation requires less CPU overhead and is more efficient at higher clockspeeds. An explanation could be that the drivers VIA supplies with this chipset were installed using the ‘Turbo Mode’, which could be the reason for the AGP 4X performing so well, as it is optimized through software.

Quake III Arena 800 MHz Benchmark Scores

Red=demo001 FPS, Green=demo002 FPS

Quake III Arena 600 MHz Benchmark Scores

Red=demo001 FPS, Green=demo002 FPS

BAPco SYSmark 2000

The SYSmark 2000 scores, however, show an entirely different picture. The Intel i820 chipset comes out on top in both the 800 and 600 MHz benchmarks, clearly taking the lead. As mentioned, the SYSmark 2000 benchmark is a rather objective and comprehensive indication of real-world performance, and thus the Intel i820 chipset’s scores have to be attributed to its high-bandwidth RDRAM memory and fast ATA-66 implementation. The VIA 694X Apollo Pro chipset is severely limited by memory bandwidth; even though the memory is running at 133 MHz with a 3-2-2 timing it isn’t even able to beat the Intel 440BX’s 100 MHz memory throughput at 2-2-2 timing, and consistently came in last.

SYSmark 2000 Benchmark Scores

SiSoft Sandra 2000

SiSoft Sandra 2000 provided us with the synthetic Dhry- and Whetstone as well as memory and multimedia scores and those actually showed that each chipset was within a few points of each other in raw CPU/FPU performance; not much of a surprise, and no need to further investigate those scores. However, the memory throughput showed a different picture. Although the benchmark isn’t designed to make efficient use of memory architecture, and the scores don't fairly represent it, this is still a good measure of raw memory throughput. In this benchmark the RDRAM really showed its muscle, besting both the VIA 694X Apollo Pro 133A chipset and the Intel 440BX.

Sandra 2000 Memory Benchmark Scores

Red=memory CPU MB/s, Green=memory FPU MB/s