NickS - I would have tried it sooner, but it is on a business machine, so I have to pick a time when its use is not critical.
loorenzo - The one posted to fix the 32GB HD bug works just fine, as that is the one I'm using now (on my M520 work machine).
If I interpret the picture right, a M530 has seperate VI/O and VCore, so you should be able to put a 233MMX in that without any trouble. You may have USB problems with the VX chipset...depending on which version is actually in your board, and what you want to run on it. On my DFI, a web camera would not stay online when switching between screens (though it was fine if I stayed on it's screen), and on my home PM7900 (M520), a scanner works just fine.
If you go to The PCChips Lottery BBS
and look in the M5xx - 586 Boards section, you may find the info you seek, plus modifications others have done to that board that may make it run even better than it was designed for. I posted some things there about my PM7900 machine that you may find useful with regard to memory, video, ethernet card, etc... See my post here
for what i've done with my VX-based DFI (400MHz !!).