Yes it is an early 486 VLB model motherboard, currently setup for a SX/DX25. 🤣 sorry could not resist. Has the cache TAG but no cache chips.
Will dig thru TH99 and see what it comes close to after dinner.....

I need the manual Please.

Looked thru TH99 but found nothing exact. Noticed that it has a 50Mhz XTAL so if a typical board a SX or DX33 should boot as a 25Mhz
Can you pull the BIOS and dump it ? Even a NIC with boot rom socket should work...

If you get the BIOS string, it will narrow it down a lot.

Intel486dx33 wrote on 2020-08-17, 14:39:

I need the manual Please.

' Siri I need the manual please'

badmojo wrote on 2020-08-18, 04:39:

Intel486dx33 wrote on 2020-08-17, 14:39:

I need the manual Please.

' Siri I need the manual please'

All Knowledge full “Luckybob” I need a manual pleez.

Vogons really needs a search engine called “Luckybob”.
Named after “Microsoft bob” or the Wizard or Dog or Paper clip.

A search engine for finding drivers, software, manuals, etc.

For example:

Search box: ct1600

Check box’s
Drivers: X
Software: X
Manuals: X

Horun wrote on 2020-08-17, 23:35:

Looked thru TH99 but found nothing exact. Noticed that it has a 50Mhz XTAL so if a typical board a SX or DX33 should boot as a 25Mhz

Just curious: Why do you assume the oscillator clock is twice the FSB clock? Most 486 boards I encountered had crystal/clock gen output equal to FSB clock, so this board would be set up for a DX50.

I did assume and a Crystal is not same as an IC Clock/oscillator. Xtals require a Buffer/Divider where most IC clocks do not as they are built in. Typical 486 motherboard with a Crystal (not a Digital clock oscillator) run at 2X the CPU frequency, I have 5 that way. If you look thru the 486 BIOS collection Topic there are about 6 with 2X Xtal (66Mhz Xtal), only one has a 1X (33Mhz) Xtal. This topic Trying to upgrade a board. is the latest with also a 2X Xtal and is very typical of single XTal 486 boards. Out of dozens of 486 boards with Xtal (not a IC Clock) I have seen just one that does not run a 2X Xtal. Yes I know there are boards that do but it really is not that common. Yes I assumed and could be wrong but did say "Noticed that it has a 50Mhz XTAL so if a typical board a SX or DX33 should boot as a 25Mhz" based on the less than a few percent of those I have have seen that do run at Xtal speed. Nearly all 286 and 386 also run Xtals at 2x cpu clock, it is the most common method with clock Xtals on a motherboard.