VOGONS


4MB voodoo and k6-2 400MHz ?

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First post, by Branco

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Only recently I found out my 1997 Pentium 200MMX might work with a K6-2 using the 2x multiplier as a 6x multiplier. The motherboard has a 66MHz FSB so that would be 400MHz. I hear that the 4MB voodoo might not like the 400MHz, so... should I start searching for a voodoo2? Or should I set the FSB to 50MHz giving total 300MHz cpu speed?

Reply 1 of 21, by PARKE

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Keep in mind that there are two types of K6-2, the Chomper and the Chomper Extended (CXT). Only the Extended version has the 2x to 6x functionality.
http://www.cpu-world.com/forum/viewtopic.php?p=148902

https://en.wikichip.org/wiki/amd/microarchitectures/k6-2

Reply 3 of 21, by matze79

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Not like 400Mhz ? i run it with a 1Ghz P3 and not encountered any issue 😳

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Reply 4 of 21, by Branco

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Hmm... not even with D3d games? I seem to recall reading something about the original 3dfx voodoo having issues with cpus above 300MHz when in direct 3d mode?

*edit: found the same claim here on the forum Re: VooDoo 1/2 CPU Choices

Reply 5 of 21, by meljor

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voodoo1 CAN give some problems/corruption on systems around p2-400 and higher. On a lot of systems it runs fine with most software, even with much higher cpu's. I could not even get a voodoo1 working on my Tusl2-c with 1400mhz P3-S and tried different brands (all working fine on slower systems). Might be the mobo...

The k6-2 is not fast enough to cause any problems, some issues might come from a high fsb (on Intel systems) and that also is not a problem in your case. 400mhz k6-2 is a good cpu to nearly maxxout the voodoo1 (it take a p2-350 to do that and yes, that's a fair bit faster than a k6-2).

asus tx97-e, 233mmx, voodoo1, s3 virge ,sb16
asus p5a, k6-3+ @ 550mhz, voodoo2 12mb sli, gf2 gts, awe32
asus p3b-f, p3-700, voodoo3 3500TV agp, awe64
asus tusl2-c, p3-S 1,4ghz, voodoo5 5500, live!
asus a7n8x DL, barton cpu, 6800ultra, Voodoo3 pci, audigy1

Reply 6 of 21, by Branco

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meljor wrote:

voodoo1 CAN give some problems/corruption on systems around p2-400 and higher. On a lot of systems it runs fine with most software, even with much higher cpu's. I could not even get a voodoo1 working on my Tusl2-c with 1400mhz P3-S and tried different brands (all working fine on slower systems). Might be the mobo...

The k6-2 is not fast enough to cause any problems, some issues might come from a high fsb (on Intel systems) and that also is not a problem in your case. 400mhz k6-2 is a good cpu to nearly maxxout the voodoo1 (it take a p2-350 to do that and yes, that's a fair bit faster than a k6-2).

Very happy! Thank you.

Reply 7 of 21, by jaZz_KCS

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I agree and can confirm based on recent experiences that the V1 will run totally fine with the AMD-K6-2/400.

You are not - by any chance - trying it on the GA-586ATX board as I were, or? Regardless, it's one of the few boards that [unofficially] supports up till 400Mhz K6-2 processors by running them in 66x6 multiplier (only with newest BIOS and without warranty).

As already mentioned, this only works with the extended Chomper (CXT) models of the K6-2. It was only when trying the V1 in a Slot1 board with a PIII-800 that artifacts started showing up for me. And this also matches the multiple user experiences littering the internet that usually talk about this to be happening at ~800 upwards. Some ppl have it running fine even at higher clockspeeds. But the FSB of 66Mhz is what the V1 actually expects, alongside a CPU with horsepower between 100 and 233Mhz. Over 100Mhz FSB may lead to errors as well.

Last edited by jaZz_KCS on 2019-08-08, 15:32. Edited 1 time in total.

Reply 8 of 21, by derSammler

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jaZz_KCS wrote:

But the FSB of 66Mhz is what the V1 actually expects. Over 100 will lead to errors as well.

The Voodoo is a PCI cards and won't get in touch with the FSB. The problem is that a faster CPU drives the Voodoo faster by providing more data to render in shorter time. This scalability was a big advantage of the card. When PCs got faster, first producers started to add heatsinks to the Voodoo cards, since they got hotter with the faster CPUs. With even faster PCs, you eventuelly reach the point where the chip runs so hot that it no longer works correctly.

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Reply 9 of 21, by jaZz_KCS

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Indeed. Also worthy of note is that this scalability also works wonder for the V2. If setup in SLI, you will get big performance boosts after surpassing ~700Mhz processors and the 2 SLI setup will get closer and closer to GF256 performance. Albeit you are reaching CPU territories here that would have been paired with way more powerful GPUs by that time. Nevertheless, it's very interesting.

Reply 10 of 21, by Branco

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jaZz_KCS wrote:

I agree and can confirm based on recent experiences that the V1 will run totally fine with the AMD-K6-2/400.

You are not - by any chance - trying it on the GA-586ATX board as I were, or? Regardless, it's one of the few boards that [unofficially] supports up till 400Mhz K6-2 processors by running them in 66x6 multiplier (only with newest BIOS and without warranty).

As already mentioned, this only works with the extended Chomper (CXT) models of the K6-2. It was only when trying the V1 in a Slot1 board with a PIII-800 that artifacts started showing up for me. And this also matches the multiple user experiences littering the internet that usually talk about this to be happening at ~800 upwards. Some ppl have it running fine even at higher clockspeeds. But the FSB of 66Mhz is what the V1 actually expects, alongside a CPU with horsepower between 100 and 233Mhz. Over 100Mhz FSB may lead to errors as well.

Actually, have not tried it yet at all, since I still have to get one.
I found an addendum (just a loose sheet of paper) to the original motherboard manual stating compatibility with the new "AMD K6 3D" cpus 233-300MHz . If only I knew this in 1999-2000 🙁
The motherboard has an intel chipset and is made by Global Circuit International.

Reply 11 of 21, by Branco

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PARKE wrote:

Keep in mind that there are two types of K6-2, the Chomper and the Chomper Extended (CXT). Only the Extended version has the 2x to 6x functionality.
http://www.cpu-world.com/forum/viewtopic.php?p=148902

https://en.wikichip.org/wiki/amd/microarchitectures/k6-2

Can I use a k6-2+ ?

Reply 14 of 21, by pixel_workbench

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I tested a Voodoo1 in a few systems, and in Windows 3D games it works fine with a 800mhz P3. But some DOS Glide games like Tomb Raider will not detect the card unless the cpu is a 450mhz P3 or lower.

On an AMD Athlon system, it usually instantly locks up or displays artifacts, even if the cpu is downclocked to 500mhz. The only way to get Tomb Raider running in Glide in this case is to disable the L1 cache, but then the game runs too slow, like single digit fps.

I've had better luck on a P4 system. A 1.6GHz P4 on a Intel chipset can run the Voodoo1 in Windows games without artifacts, but Tomb Raider would not detect the card. Amazingly, on a SIS chipset I can use even a 3.06GHz P4 and it works flawlessly in both Windows and DOS 3D games.

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Reply 16 of 21, by jaZz_KCS

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Eh, especially when running it at 2x interpreted as 6x (6x66), the AMD K6/2-400 Chomper Extended will not exceed "luke warm" temps.
I ran it with a PMMX cooler without a fan attached and it was fine. After adding a fan the passive heatsink remained cold.

Reply 17 of 21, by CoffeeOne

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Branco wrote on 2019-09-14, 14:50:
PARKE wrote:

Keep in mind that there are two types of K6-2, the Chomper and the Chomper Extended (CXT). Only the Extended version has the 2x to 6x functionality.
http://www.cpu-world.com/forum/viewtopic.php?p=148902

https://en.wikichip.org/wiki/amd/microarchitectures/k6-2

Can I use a k6-2+ ?

Please deliver a good picture (or better 3 or 4 of it, for example details of chipset and cache sram chips, ...) of the used mainboard.
That's informative and makes such posts entertaining.

EDIT: You should have done that 7 months ago already.

Reply 18 of 21, by Branco

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jaZz_KCS wrote on 2020-03-24, 14:34:

Eh, especially when running it at 2x interpreted as 6x (6x66), the AMD K6/2-400 Chomper Extended will not exceed "luke warm" temps.
I ran it with a PMMX cooler without a fan attached and it was fine. After adding a fan the passive heatsink remained cold.

that is good to know... Because I allready turned the pc on. Take a look at my 678Mhz 586 Cyrix cpu :-p 🤣 https://ibb.co/ssKC7Bv

Reply 19 of 21, by Branco

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CoffeeOne wrote on 2020-03-24, 16:32:
Please deliver a good picture (or better 3 or 4 of it, for example details of chipset and cache sram chips, ...) of the used mai […]
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Branco wrote on 2019-09-14, 14:50:
PARKE wrote:

Keep in mind that there are two types of K6-2, the Chomper and the Chomper Extended (CXT). Only the Extended version has the 2x to 6x functionality.
http://www.cpu-world.com/forum/viewtopic.php?p=148902

https://en.wikichip.org/wiki/amd/microarchitectures/k6-2

Can I use a k6-2+ ?

Please deliver a good picture (or better 3 or 4 of it, for example details of chipset and cache sram chips, ...) of the used mainboard.
That's informative and makes such posts entertaining.

EDIT: You should have done that 7 months ago already.

Yes I know. Sorry. Here goes a photo with the model to get you going.

https://ibb.co/Zg1J7gR would love to know about k6+