First post, by tpowell.ca
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Hi guys,
so after having many discussions with feipoa about cache effects, EDO vs FPM on 486 chipsets and running many benchmarks on my end, I seem to have discovered an odd problem with the DOOM benchmark on Phil's benchmarking suite. Or at least a compatibility issue with my hardware.
Basically, the demo would run in all cases on the test machines: AMD 5x86-160 (40x4) with different settings for wait-states and cache speeds, Writing Policy (WT vs WB) and cache sizes (0, 256, 512KB).
What I noticed was that, on any setting but the fastest (0 WS, cache 2-1-1-1) the demo would act as if the character input was ahead of where the game actually was, causing the character to run in circles, hit walls and shoot in seemingly arbitrary directions.
I tried to replicate this problem in DOSBOX with different cycle counts, but it always ran as intended.
Has anyone seen this before?
In short, regardless of the above, my conclusions were that on UMC PCI chipsets (BIOSTAR MB-8433UUD and Shuttle HOT-433v4) EDO memory made no measurable difference. I did not however see stability issues with EDO that feipoa has seen, but I did not push my system beyond a 40MHz bus speed.
Also, L2 cache size 256 vs 512 made virtually no difference whereas cache speed made a clear measurable difference.
In fact, slow cache speeds such as 3-1-1-1 or slower had nearly no performance benefit over NO L2 cache.
I'll give benchmark data to back this up.
- Merlin: MS-4144, AMD5x86-160 32MB, 16GB CF, ZIP100, Orpheus, GUS, S3 VirgeGX 2MB
Tesla: GA-6BXC, VIA C3 Ezra-T, 256MB, 120GB SATA, YMF744, GUSpnp, Quadro2
Newton: K6XV3+/66, AMD K6-III+500, 256MB, 32GB SSD, AWE32, Voodoo3