PCI is overclocked at 75 and 83MHz. 75 is usually not a big issue, but 83 can be. I wouldn't recommend 83MHz on a TX motherboard.

Non-Intel chipsets could find ways to keep PCI in spec when the system bus was being overclocked, but that usually meant it was being run asynchronously, so a pretty big performance penalty was usually the result.

Overclocked PCI is quite desirable for 3D accelerators.

This will be for a fast DOS PC, so no 3D acceleration will be used. It will be running Quake in software mode though. CPU is an mII-PR266GP (2x75MHz). So am I better off going with a 430TX board or an Aladdin IV+ for this build?

VIA and Alladin chipsets (pre-SuperSocket7) are slower.

appiah4 wrote:

This will be for a fast DOS PC, so no 3D acceleration will be used.

But you know, that DOS gaming is where 3dfx Voodoo and Voodoo 2 really shines, right? 😀

HanJammer wrote:

appiah4 wrote:

This will be for a fast DOS PC, so no 3D acceleration will be used.

But you know, that DOS gaming is where 3dfx Voodoo and Voodoo 2 really shines, right? 😀

Aside from Tomb Raider and Screamer 2 I don't know of any other DOS glide games I would be really interested in..

nearly no Socket 7 Chipsets that have a 2/5 PCI divider. Actually, nothing aside from Aladdin IV seems to have a divider for Socket 7

PCChips M537 (the one with VIA VP) can set the PCI to 33MHz when using 75/83MHz bus.

CPU is an mII-PR266GP (2x75MHz)

Surely it's a 2.5x multiplier?

37MHz PCI is unlikely to be a problem, I used it a lot back in the day. As far as video cards go, my Trident 9680 works at 60MHz PCI so who knows.

bakemono wrote:

nearly no Socket 7 Chipsets that have a 2/5 PCI divider. Actually, nothing aside from Aladdin IV seems to have a divider for Socket 7

PCChips M537 (the one with VIA VP) can set the PCI to 33MHz when using 75/83MHz bus.

Well.. Are you sure the option to lock it actually works? Because the page I linked above says only VPX and VPX/97 can run 75MHz and only at 1/2 divider or Asynch (whatever that implies?)

bakemono wrote:

CPU is an mII-PR266GP (2x75MHz)

Surely it's a 2.5x multiplier?

37MHz PCI is unlikely to be a problem, I used it a lot back in the day. As far as video cards go, my Trident 9680 works at 60MHz PCI so who knows.

Yeah it's 2.5x my bad 😀 I'm pretty excited about trying a Cyrix mII for DOS actually..

Something built upon SiS 5595 chipset may be good choice for Cyrix, because of chipset optimization especially for Cyrix. I had Gigabyte GA-586SG, but there is also ATX variant of it GA-586SGM and 100MHz supported version GA-5SG100.

appiah4 wrote:

This will be for a fast DOS PC, so no 3D acceleration will be used. It will be running Quake in software mode though. CPU is an mII-PR266GP (2x75MHz). So am I better off going with a 430TX board or an Aladdin IV+ for this build?

If you can find a good board with it, the Aladdin IV+ is definitely the better choice, with divider options and clock-for-clock the highest performance of any So7 chipset. However good boards with Aladdin IV+ are few and far between; I've usually seen it on limited Acer OEM boards or on shoddy PC-Chips things. That said, the fastest So7 board I ever benchmarked was the PC-Chips M560. It seemed stable even despite low build quality. Biostars' M5ATA was vastly better-built, but even with all settings tuned it was 11% slower that the M560. That still put it on par with the fastest i430TX boards I had.

Note regarding PCI dividers: you don't have to use them - so if you want to OC the PCI bus for more performance, having the option to divide down the PCI speed doesn't stop you trying.

What I have at hand is also a MB560TG.

appiah4 wrote:

What I have at hand is also a MB560TG.

Well, they don't come faster than that. Hope it's stable though...

Well.. Are you sure the option to lock it actually works? Because the page I linked above says only VPX and VPX/97 can run 75MHz and only at 1/2 divider or Asynch (whatever that implies?)

Well, it's not like I checked it with a scope at the PCI slot, but changing the jumper between 33MHz or FSB/2 did show some difference in benchmarks.

Pcchips m571 has both synch and asynch

I always rAn overclocked pci 83mhz FSB, good speed bump with decent pc100 sdram.

Too bad I had to run an old bios to fit 256mb of sdram though.