single v. dual voltage



New Member

I am trying to figure out what single v. dual voltage on the motherboard is. Whenever I put in a Pentium 150 (which uses 3.52 Single voltage type) into my Soyo sy-5stm motherboard, the system works fine. But when I put in a Pentium 233 MMX (which uses 2.2V dual voltage type), windows won't run or install because scanreg keeps finding errors and tells me to reboot. I'm thinking that the dual voltage is not working. Have any ideas? Could it be something else? What exactly does single v. dual voltage mean? The installation guide tells me to make it dual for Pentium MMX. Can I just use Single? Is that even my problem in the first place?
Thanks in advance.


New Member
OK, this isn't 100% certain, but I feel I'm on pretty steady ground on this. Non MMX, older pentiums used a single voltage level over the socket, providing even power to the whole chip. As I understand it (please correct me if I'm wrong) MMX supporting sockets have a 'dual plane' voltage setup, providing one power level to parts of the chip and a different level to others. I remember having a small socket-to-socket adaptor in my pc at one time because I was running an MMX cpu in an older board, the adaptor changed the voltages to what the MMX chip wanted. I'd imagine that this voltage mismatch is what's causing the (assumedly) math errors that are glitching your pc out.

And the beat goes on...


New Member
Thanks for the advice. Well I put the voltage on the correct setting for Pentium 233 MMX and it still didn't work so I got another 5stm motherboard in case the first one was defective. But the other one would not work either. I just don't understand why Win98 will only install when there is a Pentium 150 installed on the Motherboard. I have 66MHz SDRAM installed, as well as a 66MHz cpu. That should match up perfectly with the 66MHz Socket 7 motherboard. Everything is supposedly supported in the manuel. I'm wondering now if it has something to do with the harddrive, which is a new Western Digital 13 gig UDMA/ATA 66 harddrive?

The only other components I have installed are the ps/2 mouse and keyboard, 3.5in floppy drive, and a 50x UDMA Digital Research CD-ROM drive.


New Member
are you sure that your cpu works with 150 ?
can you set your multiplier on 2.27272727...?

--> it has nothing to do with your harddrive. it is cause your cpu is not stable enough, i think. verify again your settings ! some mb manuals are very incorrect. the manual of my ga-5ax tells my, that it is possible to put up the fsb up to 150, but that is not feasible with this board.