VOGONS


First post, by Yoghoo

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Got two Socket 7 motherboards:

Also got 2 CPU's for these motherboards:

  • Intel Pentium MMX (200Mhz)
  • AMD K6 (233Mhz)

Both are running stable but need to store/sell one of those motherboards and CPU's as I want to use the case for another build (and got no more room left 😀).

Question is which one of the motherboards and CPU's I should keep. For example which CPU can be slowed down the most for DOS, which motherboard is the most stable, best caps etc.

So if someone has some advice or experience please let me know.

Reply 1 of 9, by majestyk

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I would keep the Gigabyte.
It has higher FSBs (and even a lower FSB - 50MHz - if you want to underclock) and is probably more versatile when it comes to diferent CPUs and voltages. The Abit relies on its limited "auto-setup" in BIOS.
4 SIMM slots and dual AT/ATX PSU connectors are good to have except when you cannot do without the 4th ISA slot.
And I remember a review on Anand´s site where he was quite disappointed of the Abit PX-5 as compared to the AX-5.

Reply 2 of 9, by Yoghoo

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majestyk wrote on 2022-12-09, 18:07:
I would keep the Gigabyte. It has higher FSBs (and even a lower FSB - 50MHz - if you want to underclock) and is probably more ve […]
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I would keep the Gigabyte.
It has higher FSBs (and even a lower FSB - 50MHz - if you want to underclock) and is probably more versatile when it comes to diferent CPUs and voltages. The Abit relies on its limited "auto-setup" in BIOS.
4 SIMM slots and dual AT/ATX PSU connectors are good to have except when you cannot do without the 4th ISA slot.
And I remember a review on Anand´s site where he was quite disappointed of the Abit PX-5 as compared to the AX-5.

Thanks. Any opinion about the CPU I should use with it? Which one is the most flexible (also for DOS) K6 or Pentium MMX?

Reply 3 of 9, by Gmlb256

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Between these two CPUs, the Pentium MMX is the most flexible. It has the TR12 registers which SetMul can use to provide additional ways to slow down the computer.

As for the motherboard, keep the Gigabyte as majestyk said. Jan has a modded BIOS that improves UDMA compatibility and allows support for K6Plus CPUs which are much better than the original AMD K6 and allows the CPU multiplier to be switched on the fly.

VIA C3 Nehemiah 1.2A @ 1.46 GHz | ASUS P2-99 | 256 MB PC133 SDRAM | GeForce2 GTS 32 MB | Voodoo2 12 MB | SBLive! | AWE64 | SBPro2 | GUS

Reply 5 of 9, by Gmlb256

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Sphere478 wrote on 2022-12-10, 17:23:

Does the 200 have the 3.5x multi or is it locked? (You’ll have to test to know) set 1.5x on mobo

No, only the 233MMX interprets the 1.5x multiplier as 3.5x around the desktop Pentium family.

VIA C3 Nehemiah 1.2A @ 1.46 GHz | ASUS P2-99 | 256 MB PC133 SDRAM | GeForce2 GTS 32 MB | Voodoo2 12 MB | SBLive! | AWE64 | SBPro2 | GUS

Reply 6 of 9, by AlessandroB

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Gmlb256 wrote on 2022-12-10, 17:30:
Sphere478 wrote on 2022-12-10, 17:23:

Does the 200 have the 3.5x multi or is it locked? (You’ll have to test to know) set 1.5x on mobo

No, only the 233MMX interprets the 1.5x multiplier as 3.5x around the desktop Pentium family.

i have one 200MMX that use 3.5x if set to 1.5x

Reply 7 of 9, by Gmlb256

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AlessandroB wrote on 2022-12-10, 17:32:
Gmlb256 wrote on 2022-12-10, 17:30:
Sphere478 wrote on 2022-12-10, 17:23:

Does the 200 have the 3.5x multi or is it locked? (You’ll have to test to know) set 1.5x on mobo

No, only the 233MMX interprets the 1.5x multiplier as 3.5x around the desktop Pentium family.

i have one 200MMX that use 3.5x if set to 1.5x

Interesting, perhaps it depends on the CPU revision.

VIA C3 Nehemiah 1.2A @ 1.46 GHz | ASUS P2-99 | 256 MB PC133 SDRAM | GeForce2 GTS 32 MB | Voodoo2 12 MB | SBLive! | AWE64 | SBPro2 | GUS

Reply 8 of 9, by Sphere478

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There is no way to know other than installing it and trying it. I have a decent amount of testing behind trying to find a correlation. It comes down to luck of the draw. Also, three cpus of same s spec can have three different multipliers at the same mobo setting. It’s bonkers.

Sphere's PCB projects.
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Sphere’s socket 5/7 cpu collection.
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SUCCESSFUL K6-2+ to K6-3+ Full Cache Enable Mod
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Tyan S1564S to S1564D single to dual processor conversion (also s1563 and s1562)

Reply 9 of 9, by Yoghoo

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Gmlb256 wrote on 2022-12-10, 17:23:

Between these two CPUs, the Pentium MMX is the most flexible. It has the TR12 registers which SetMul can use to provide additional ways to slow down the computer.

As for the motherboard, keep the Gigabyte as majestyk said. Jan has a modded BIOS that improves UDMA compatibility and allows support for K6Plus CPUs which are much better than the original AMD K6 and allows the CPU multiplier to be switched on the fly.

Many thanks for mentioning the modded BIOS. I had to disable DMA before because it was unworkable slow (starting Windows 98 took 10+ mins for example). Just flashed it and it seems DMA is working without problems now.

Sphere478 wrote on 2022-12-10, 17:47:

There is no way to know other than installing it and trying it. I have a decent amount of testing behind trying to find a correlation. It comes down to luck of the draw. Also, three cpus of same s spec can have three different multipliers at the same mobo setting. It’s bonkers.

Thanks. Will try if it works in a couple of days.