440bx 133mhz bus mod

[ottothecow]

I have often read about how the 440BX chipset was able to run a 133mhz bus PIII even though it didnt technically support it and I am sure that there is someone here who has done this before.

My problem is that I have a new intel server board (n440bx) and two 733mhz PIIIs but I cant get it to boot (or at least show video). It boots and shows video when I stick in two PII 333's through the integrated video but I cant seem to get it to show video on an ancient PCI video card that I have (an S3 Virge). When I put in the 733mhz cpus, neither the pci card or the integrated video will wake the monitor out of standby. I understand that the original issue of the 440bx chipset was that while it had a suitable PCI divider, it would run AGP cards too fast. This board doesnt even support AGP so I would assume that that problem wouldnt be an issue.

What do I need to do to make this system start? Is there some option I need to change to make the PCI divider switch or do I need to find a better PCI video card somewhere?

 

[ottothecow]

I suppose this thread should really be moved out of here to the techinical support or motherboard forums but I dont want to double post (mods, if you see this)

 

[implicit1]

This is going way back, but IIRC you need to modify something to get a coppermine P3 to run on a BX board. I think I remember people using socket adapters or rewiring the socket itself. In any case, I know it wasn't as simple as plugging in a P3 and it firing right up.

 

[NewBlackDak]

If it's an Intel board before AGP then it'll just boot with 100MHz FSB, so you'll only get 550 from the 733's. You might see if there is a BIOS update somewhere. Also, are you running Slotted PIII's or on a slocket? If on the slocket the settings might be wrong.
Have you tried one of the 733's at a time to see if maybe one of them is just bad?

 

[Zap]

Ahhh, the venerable BX chipset. I've done a lot of overclocking with these, including running one at a full 150MHz FSB (with a PCI Voodoo3, tried many AGP cards and none would work at those speeds).

The "modding" to be done is to get a Tualatin chip working on the BX chipset. If this board works with the Pentium II chips, but so far doesn't with the Pentium III, perhaps it is a problem with the power circuitry. Just like some boards won't take Prescott Pentium 4 chips but can take the same speed Northwoods, some older Slot 1 BX chipset boards can't take Coppermine chips while they can take the Klamath chips. If the board doesn't have the physical support for the voltages needed, then it just won't work regardless of bus speed. If it did work, then the only "problem" would be that the CPUs would be underclocked to 550MHz.

There's an additional problem in that it is an Intel server board. Server boards typically don't have overclocking and Intel branded boards also generally don't have overclocking. Even if the board did support Coppermine chips, you'll never run them at full 733MHz.

 

[NewBlackDak]

I had a 1GHz Tually running in a BX-133 Raid at 10x150. I actually had a Radeon 64MB DDR VIVO flashed to SE that handled the 100MHz AGP just fine. I finally gave it up when I broke a pin in the socket trying to do a vmod with wires. I sold it to someone who is good with a soldering iron(and has good eyes), and he got it running again. In fact I still have the video card running in my HTPC.

Oh the memories.

 

[Zap]

Yeah, I had my BX133-RAID running a Tualatin also. The one I got running 150MHz FSB was a P3 550@825 on an Asus P3B-F. The Abit BX133-RAID will let you lower AGP to 1X while the Asus P3B-F didn't have that option. I think it's what made the BX133 so overclockable with AGP cards.

 

[dexvx]

Most later BX can run 133 FSB. However, they did so with the AGP out of spec, at 89Mhz (newer BX's had a 1/4 PCI multiplier that ran the PCI bus at 33Mhz, in spec). The AGP was the only thing out of spec, so as long as your AGP card can handle it, its fine.