https://manualzilla.com/doc/7401820/aopen-mx6 … on-guide?page=2

Apparently 133mhz is 'for internal testing only' and 'may damage the chipset'.

https://en.wikipedia.org/wiki/Intel_440BX

"Unfortunately, running a 440BX above 100 MHz FSB resulted in the AGP video card being forced to run on an overclocked AGP bus, as the 440BX only had "2/3" and "1/1" bus dividers. Some video cards were tolerant of this, such as various early NVIDIA GeForce cards, but more than a few were unstable with a 35% AGP overclock.[2] The PCI bus was not affected by this problem (there was a "1/4" bus divider for the PCI bus on the 440BX) so users could use a PCI graphics card in lieu of an AGP one. However, this inflicted a performance penalty on graphical performance since PCI has significantly lower bandwidth throughput than AGP. "

So.....probably, if you don't use AGP. If you do use AGP, it could be hit and miss. Could you use the CPU at 7.5x100 I wonder or are they multiplier locked at a CPU level? From what I have read, 5.5 @ 100 might work (albeit slower - obviously). You might also find that you can get the bus speed up to 112mhz if your AGP card isn't stable at 133mhz.

So you probably want this thread Video cards known to operate stably on an overclocked AGP bus&

And if the realisation didn't hit you yet, to be told a 440ZX is a slightly crippled 440BX so everything said about BX boards applies, unless they start talking about 3rd or 4th memory slots and over 512MB of RAM.

Anyway, I'd try firing up the board at 100, forced setting, it's not gonna do auto with a 133 CPU, and if it boots you're good to go at 133... if it doesn't then you're probably lacking a microcode update in the BIOS for B stepping PIIIs.

440ZX is just 440BX with 512 Mb RAM limit and without SMP.

Account AGP overclock: at 133 you'll run the AGP bus at 83MHz instead of the usual 66. Myself I run a P3B-f board (440BX, later one) with a 140MHz bus stop the AGP gets closer to 89MHz. Rock stable with my Ti4200. The MX440 I had in it before was rock stable at 150MHz fsb / 100MHz AGP. So if you're using a graphics card from the Gf4 generation I think you're good to go for AGP.

Bios microcode: I wouldn't know, you just have to find out I guess. It's a good thing to update too the latest BIOS version, maybe the right support for the CPU is known?

Thank you for the help. I am using an MX440 128bit so it sounds like that's a better card for a faster bus overclock.

How about the CPU voltage will that be a problem?

Almoststew1990 wrote on 2021-08-08, 17:48:

Thank you for the help. I am using an MX440 128bit so it sounds like that's a better card for a faster bus overclock.

How about the CPU voltage will that be a problem?

According to the manual:
"the CPU core voltage is automatically detected, the range is from 1.3V to 3.5V. "