I'd suggest an ISA card and dual boot between PCI and ISA. See this thread: 486 Mobos: Can you install multiple VGA cards - like AGP/ PCI switching?

Don't need to find a graphics card that works at such low speeds. As long as it work in VGA mode you can always create another entry in "boot.ini" with the "/basevideo" parameter, which will force it to use the generic VGA driver.

j^aws -

I'd suggest an ISA card and dual boot between PCI and ISA.

I'm affraid of ISA graphic cards and as I look there: Eliandas ISA VGA card roundup
...the nice Tseng ET4000AX gfx card is kinda overpriced today: http://www.ebay.com/itm/Fruhe-original-Tseng- … =item43e186be2a

But the major problem is this - how do you know, that at the 7.14MHz FSB setting it will work at all? What if the ISA bus is just as slow, as the PCI?

alexanrs -

Don't need to find a graphics card that works at such low speeds. As long as it work in VGA mode you can always create another entry in "boot.ini" with the "/basevideo" parameter, which will force it to use the generic VGA driver.

That is good idea. Hopefully I can manage 800x600 in 16 colors too... or is there any way to get 256 colors?

And the boot.ini looks this way:

1[boot loader]
2timeout=3
3default=multi(0)disk(0)rdisk(0)partition(1)\WINDOWS
4[operating systems]
5multi(0)disk(0)rdisk(0)partition(1)\WINDOWS="Microsoft Windows XP Professional" /noexecute=optin /fastdetect

Where I should be adding the /basevideo ...? After the /fastdetect?

1[boot loader]
2timeout=3
3default=multi(0)disk(0)rdisk(0)partition(1)\WINDOWS
4[operating systems]
5multi(0)disk(0)rdisk(0)partition(1)\WINDOWS="Microsoft Windows XP Professional" /noexecute=optin /fastdetect
6multi(0)disk(0)rdisk(0)partition(1)\WINDOWS="Microsoft Windows XP Professional (VGA mode)" /noexecute=optin /fastdetect /basevideo

I believe you can use the above and have two boot entries: one using the regular driver (for normal+OCed operation), and a second entry that enables VGA only. I'm not sure it can do anything other than 640x480, but since you are just a reboot away from using the fully fledged driver, this shouldn't but much of an issue.

I'm affraid of ISA graphic cards and as I look there: viewtopic.php?f=46&t=41662
...the nice Tseng ET4000AX gfx card is kinda overpriced today: http://www.ebay.com/itm/Fruhe-original- ... 43e186be2a

But the major problem is this - how do you know, that at the 7.14MHz FSB setting it will work at all? What if the ISA bus is just as slow, as the PCI?

I can't imagine an ISA card would be any worse than a severely underclocked PCI card. I don't know if the ISA would be underclocked too.
Even if it were, I bet ISA cards are more tolerant to it. I would try almost any ISA card you CAN get your hands on

The issue might be that in many motherboards the ISA bus run at a speed that depends on the PCI bus. Stuff like PCI/4 or PCI/3 are common enough. Running a vídeo card under 1MHz might be pushing your luck a bit too much.

trodas wrote:

But the major problem is this - how do you know, that at the 7.14MHz FSB setting it will work at all? What if the ISA bus is just as slow, as the PCI?
...

I've ran ISA VGA at ridiculously slow speeds:

As mentioned by alexanrs, ISA clock can be a fraction of the PCI clock, but sometimes boards let you fix it at 7.14MHz - check your BIOS settings. As mentioned by smeezekitty, try any ISA card for testing - doesn't need to be anything fancy. Sometimes, it's a matter of trial and error until something works...

I'd stay away from ISA cards with that build though. You have mentioned that you also wanna run it with the bus OCed to 83MHz, and honestly you'd just waste the processor with a card slower than the S3 Trio 64 in DOS games. Unless running Windows at higher resolutions when the PC in that "super de-turbo mode" is a must, I'd just stick to running Windows in VGA mode in those ocasions. Even if you do get an ISA card working at higher resolutions, I'd not run the desktop at anything higher than VGA anyway, just to allow the PC to be a little less sluggish.

^^ With the right ISA card, you can dual boot with a PCI card too...

Good news! I get from friend a ATI Rage XL PCI card. A old, 8MB videoram suxxka, but even in VGA mode it offer 1024x768...! So now I can try, if I will have accelerated graphics at 10.7MHz...! Looks good, is not it?

So the problem is solved - ATI Rage XL does the job for me. Tough I"m very curious, as why/how S3 Trio64 make the board works fine at 83MHz FSB (41.7MHz PCI clock), but when using ATI Rage XL I have to downclock to 75MHz FSB. But that give me a reason to perform the BSEL = 0 mod to get the card working at 83MHz FSB for SPEEEEEEEEEEEEEED 😀

^^ Congrats! BTW, sometimes 83/75 MHz stability is sensitive to BIOS settings; try playing around with relevant ones.

Well, I tried, but no help. Can you suggest the "relevant" ones? I tried:

- increasing PCI latency to 96 (default it 32, but with the overclock, I need for SuperPi 32M stability go to 42 🙁 But I get best P90 result ever: http://hwbot.org/submission/2978646_ ) - no change

- increasing the error waits to retry from 1 on the PCI bus to 4 (max) - no help either

- disabling all the other 3 PCI slots - no change in behaviour

So I quess a hardware mod is the best way. I hope I get the Rage XL working on 83MHz and perhaps I can even lower the PCI latency? We see... Maybe things will be different with the PATA to CF reduction?

trodas wrote:

Well, I tried, but no help. Can you suggest the "relevant" ones?

Others to try:

- Passive Release
- Delayed Transaction
- Memory timings
- Video ROM shadowing
- Video BIOS Cacheable

trodas wrote:

Maybe things will be different with the PATA to CF reduction?

Also, could try:

- PCI IDE DMA modes
- Off-board IDE/ SCSI controllers

Sometimes, with trial-and-error and a bit of luck, a certain combination of the above may work.

Can you suggest the "relevant" ones?

- Passive Release

Tried, no luck.

- Delayed Transaction

Tried, no luck.

- Memory timings

Not tried, doubtfull that it made any difference...

- Video ROM shadowing

Tried, no luck.

- Video BIOS Cacheable

Tried, no luck.

- PCI IDE DMA modes

Not tried, intresting, but useless in the end. I want overclock for speed, not to lack the speed...

- Off-board IDE/ SCSI controllers

Did not have one, cannot try then. And I believe it could be much easier to just to the board BSEL = 0 mod to lock the PCI bus frequency. Don't you agree???

^^ Sure, BSEL = 0 looks trivial. But with any hardware mods, always be prepared to sacrifice the board if it doesn't go according to plan...!

I use radeon 7000's in all my old computers. I haven't really found a board that it doesn't work in.

^^ Sure, BSEL = 0 looks trivial. But with any hardware mods, always be prepared to sacrifice the board if it doesn't go according to plan...!

True. I never lost board because of mod, but it indeed can happen. Still, if overclocking the bus to 41.5MHz poses no problemo for the ATi Rage XL - AND - the CF card running on the cenversion, then there is a little reason for it.
The only one problem is the missing ability to set the card as fixed device. W/O that, no second partition will be visible... not to mention the impossibility to install WinXP on removable device...

I use radeon 7000's in all my old computers. I haven't really found a board that it doesn't work in.

Rage XL PCI does this trick for me 😀 Radeon 7000 seems to new for me anyway. It will be probably hard to get drivers for WinNT on it, right? 😀 But for my ATI Rage XL it is not a problem:
http://depositfiles.com/files/h5sl7hffg
http://www.mediafire.com/?rnddw5lcbtr7uj1
https://mega.co.nz/#!XEMAQBhK!q5hwMlRm0EETsCp … d10adQJBOI7Fk8k

Beat that! 😀