Pentium III 800 will not run in old Compaq Deskpro

L

LOLZpersonok

New Member
This seems to be the best forum for this thread. I know everyone else's post here is about new processors, but I didn't see any forum for older computers. So, I figured I'd post here. I'm new, and I don't know of any other forum at this site that would be better for this post. So please don't publicly execute me! :o

Anyways, that aside, I have an old Compaq Deskpro. Its case design is an uncommon one, but the internal design is basically the same as all the other ones. A while ago, I bought an 800MHz Pentium III to upgrade the Deskpro from its stock 500MHz Celeron. While the sockets do match, the FSB speeds don't, which I have a feeling may be preventing the Pentium III from working in the Deskpro. I know that some computers automatically change the FSB speed to match the processor, or the processor changing its FSB speed to match the computer. As for specifics, the FSB speed in the Compaq Deskpro is 66MHz, and the Pentium's FSB speed is 133MHz.

This very same Pentium III does, however, work in a Compaq Presario which has a 100MHz FSB speed and an 850MHz Celeron. This Presario's processor, which is an 850Mhz Celery (I have a habit of calling Celerons Celery) and has a 100MHz FSB also does not work in the Compaq Deskpro. What is a little odd, is how when either the 850MHz Celeron or the Pentium III is installed, rather than POSTing, the Deskpro will simply ramp its only fan up all the way, even faster than the highest setting in the BIOS. This only happens if the fan speed is set to automatic in the BIOS.

With this Deskpro, I have not been able to figure out how to change the FSB speed. The BIOS is locked down and it cannot be changed from there. This may be a long shot, but is there any way that anyone could suggest to make this Pentium III (Or the Presario's 850MHz Celery) work in this Compaq Deskpro?
 
Last edited:
You'd need to check some old documentation. It's probably not a supported processor. Just because it fits the socket doesn't mean it'll work.
 
A lot of those boards had jumpers for FSB.
What specific model was it?

Also, a lot of the older chipsets didn't support the newer P3 and similar, so you wouldn't have compatibility upwards. It could be entirely possible for you to have something like a 440LX board with the 500 Mendocino Celeron which wouldn't support upgrades to Pentium III
 
beers said:
A lot of those boards had jumpers for FSB.
What specific model was it?

Also, a lot of the older chipsets didn't support the newer P3 and similar, so you wouldn't have compatibility upwards. It could be entirely possible for you to have something like a 440LX board with the 500 Mendocino Celeron which wouldn't support upgrades to Pentium III
Click to expand...

This is a Deskpro ENS C500 with I think to be an Intel 810 chipset. It's old (from roughly 1999 or 2000), so I'm thinking that there is a good possibility of it not supporting the P3 processors.

I just looked it up. It does appear that my Deskpro is a Mendocino based system, so it isn't compatible with the P3. Oh well, so much for upgrading. Thanks for the help.

EDIT: This is totally off-topic. These particular Deskpros are interesting. Their internal date codes (I had two of these machines, I got rid of one) state that they are from 1999. They're designed for Windows 2000 and Windows 98, which isn't the weird part. What is the weird part is that they have COA stickers for Windows 95. I just thought that was unusual.
 
Last edited:
Its not going to work, it wont clock back that far. The bios probably doesn't even recognize it. Even if it did, with a 66mhz bus and the Pentiums multiplier it would run at 400mhz.
 
You must log in or register to reply here.
Back
Top