What do you plan to do with the C3? Their performance is pretty lackluster.

True that the performance is lackluster, but an obscure processor that's the last of the Cyrix chips (though made by for VIA by Centaur) that has a meager 10w TDP that can be cooled by little more than a low flow case fan and a large heatsink, a true silent machine. Plus I've always been interested in getting one running, I used to have a C3 800 a friend gave me, but I never got a working board for it and eventually lost it in a move.

So I see 2 problems basically:
1)Will the board work with 133FSB CPU's
2)Is the Cyrix chip functional (because that may just be the case, though not that likely)

Do you have another s370 board to test your Cyrix chip?
I took a dive into the boards manual (easy findable with google) and unfortunately it doesn't have jumpers you can use to force it into 100Mhz FSB. It's all in the BIOS.
Have you tried first setting the BIOS to 100Mhz FSB (instead of automatic)? That may help in getting the Cyrix chip to work, though it will be underclocked. The Cyrix chip can I think be unlocked using a small util that sets it's multiplier (it's multiplier can supposedly be changed using software) so you can up the multi once you get it all working.
It's very well possible your i810 chipset simply can't manage 133Mhz and was downbinned to be 100Mhz max?

Frankly, I'm not a fan of i810 boards. Getting a i815 Coppermine board shouldn't be hard but perhaps you want to simply use whatever you have available.

For better joy joy feelings, you need to apply sum sand paper to those rust spots in that case.

Tetrium wrote:

So I see 2 problems basically: 1)Will the board work with 133FSB CPU's 2)Is the Cyrix chip functional (because that may just be […]
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So I see 2 problems basically:
1)Will the board work with 133FSB CPU's
2)Is the Cyrix chip functional (because that may just be the case, though not that likely)

Do you have another s370 board to test your Cyrix chip?
I took a dive into the boards manual (easy findable with google) and unfortunately it doesn't have jumpers you can use to force it into 100Mhz FSB. It's all in the BIOS.
Have you tried first setting the BIOS to 100Mhz FSB (instead of automatic)? That may help in getting the Cyrix chip to work, though it will be underclocked. The Cyrix chip can I think be unlocked using a small util that sets it's multiplier (it's multiplier can supposedly be changed using software) so you can up the multi once you get it all working.
It's very well possible your i810 chipset simply can't manage 133Mhz and was downbinned to be 100Mhz max?

Frankly, I'm not a fan of i810 boards. Getting a i815 Coppermine board shouldn't be hard but perhaps you want to simply use whatever you have available.

Well, I haven't received the C3 733 yet... however I'm hoping to get the system (or a system) ready for the C3 once it gets here. However I have a strong feeling that I'm outta luck.

Yeah, I've heard sketchy reports regarding the i810 boards, they were essentially 100MHz FSB Intregrated Graphics chipsets, meant for cheap systems based on Mendocino Celery chips. The BIOS appears to have FSB overclocking options (up to 166 FSB!), but that would mean running the chipset well beyond spec. The i810E was a later version that could run at 133MHz FSB, to which the AOpen MX3W Pro-E is based (Mine is Pro-V), however they share the exact same BIOS file - which gave me hope. I think the best thing I could say about this AOpen board is "It was free", so the price was right.

I have 3 CPUs I tried in it that use the 133MHz FSB, a 1000, 800 and a 733. If there was a bad chip, I could see one not working but not 3. The PIII 650 (6.5x100) I normally use in the system works fine. I think what I have on my hands is a board that simply will not run a 133 FSB chip, even if downclocked to 100 FSB. Leaving me with 2 options.
A) Find a C3 with a 100MHz FSB, or
B) Find a mATX S370 board that can run a C3 with a 133MHz FSB.
Not exactly an easy task if I wanna keep it cheap.