VOGONS


First post, by Verdorie1

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So I own a Gainward 3DFX Voodoo 4MB and I decided to dabble with some overclocking.
I read that I could specify a clock speed in my autoexec.bat by adding the line SET SST_GRXCLK=##.
Now from what I gathered the Voodoo 1 is supposed to run at 50MHz by default. I try to find a stable clock speed and do some benchmarking. 51MHz was all I could get stable...

In Quake 1 my fps was 27.0 in Timedemo 1 without adding the line to my autoexec.
The strange part is that when I add "SET SST_GRXCLK=50" my framerate jumps to 33.1.
Could it be that my Voodoo wasn't running at 50MHz?
Or could this be a side effect of my P1 MMX running at 75MHz bus instead of the default 66MHz?

My 3D performance didn't go down when I changed the bus speed.

Anyone got any idea what's going on?

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Reply 1 of 6, by Munx

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Verdorie1 wrote on 2024-10-29, 18:18:

could this be a side effect of my P1 MMX running at 75MHz bus instead of the default 66MHz?

None of the Voodoo cards I came across could get past a few MHz beyond 50. Its just the way they are. And yes, that 75MHz bus isn't helping. Going back to 66 would likely get you extra 1-2 stable MHz which is in line with most Voodoo 1.

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Reply 3 of 6, by havli

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The default clock depends on the drivers I think. There is no BIOS on Voodoo Graphics (or Voodoo2 for that matter) to store the default clock. And yes, some drivers might default to 45 MHz.

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Reply 4 of 6, by sdz

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At least for the V2, some FBI config straps were dedicated for setting the clock. I haven't tested if they were actually used, but the driver could check those straps and set the clock. Might be similar for the original Voodoos.

Reply 5 of 6, by Spark

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I had a Voodoo 1 up to 57mhz stable with heatsink+ fan. This was on standard speed PCI bus. It was one of those Guillemot voodoo 1's that apparently are supposed to be run at 45mhz. 58mhz was unstable.
Without heatsink+ fan it was unstable even at 50mhz.

Reply 6 of 6, by Imperious

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I've had my Diamond Monster Rev D card running as high as 57mhz in the past.
I wonder if the memory is what is limiting some of the cards, or were later revisions of the chipset ic's capable of better speeds
due to improved silicon?

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