Asus P/I-P55T2P4 supports 83 MHz

Also I do remember “back in the day” people modifying the FSB clock circuitry
The infamous PCCHIPS m571 would run 108mhz FSB after modification

I believe some have gotten the TX to 90mhz FSB by increasing the boards IO voltage to the chipset above the normal 3.5

I do not know of any HX board with native OEM support beyond 83mhz FSB

If you replaced the clock crystal, you might achieve something a little faster than the 83 MHz that can be achieved with the stock board, but that would of course put the PCI bus even further out of spec. You can set it to 108 MHz by the jumpers, but it won't post.

I would guess higher FSB might be feasible, but you're going to have to make sure you use PCI cards that conform to the 2.2 spec and have fast enough RAM.
Because the PCI divider can only be set to 2, you need to run the bus grossly out of spec. Newer cards support 66MHz so should be able to handle that assuming the bus doesn't give out.
RAM is a bit of a problem. As the HX chipset doesn't support SDRAM, I'm not sure how you're going to get stuff rated for 100MHz. HX supports EDO SDRAM though....was that made as PC100?

Personally, I think the TX chipset would be a better choice for this project.

Anonymous Coward wrote on 2021-12-11, 01:26:

I would guess higher FSB might be feasible, but you're going to have to make sure you use PCI cards that conform to the 2.2 spec […]
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I would guess higher FSB might be feasible, but you're going to have to make sure you use PCI cards that conform to the 2.2 spec and have fast enough RAM.
Because the PCI divider can only be set to 2, you need to run the bus grossly out of spec. Newer cards support 66MHz so should be able to handle that assuming the bus doesn't give out.
RAM is a bit of a problem. As the HX chipset doesn't support SDRAM, I'm not sure how you're going to get stuff rated for 100MHz. HX supports EDO SDRAM though....was that made as PC100?

Personally, I think the TX chipset would be a better choice for this project.

I was wanting the 512 mb max ram option. Since tx doesn’t do much faster with sd ram, seems more ram is more valuable than less slightly quicker ram also the xt can only cache 64 mb whereas the hx can cache 512mb

Not always a problem though, most of the time I’m using a k6 3+ Which allows 256mb cached on tx

It's a bit of a lottery whether your specific piece of a models production will actually even be stable at 83Mhz or not, I've had it both ways, boards that other ppl swear are 83 stable, being unstable, boards that ppl say are unstable at 83 working fine for me, with use of known to be good at 43Mhz PCI cards of course, CPU below rated frequency and overkill RAM spec. The later boards tended better, that may be more due to the tuning up and better yields of the chipset silicon than designs of the boards getting tweaked, could be both.

I recall talk of some 430VX boards having undocumented settings, 90Mhz, favored for a year maybe by Cyrix overclockers before super 7 boards became widely available, or cheaper. I can't remember the boards involved, stuff like that was talked about on [H]ardOcp while it was still more BBS style before it became vBulletin style, so 97-99ish I think. Doubt archive.org has captured much.