Underclocking slot 1 PIII on i810

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SixToes
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Underclocking slot 1 PIII on i810

Post by SixToes » Fri Apr 29, 2005 4:26 am

Hi,

I'm building a ghetto style super-cheap-all-2nd-hand-off-ebay server based on a MicroStar MS-6183 i810 mobo. It looks like it only supports 100MHz FSB, so my question is this - if I get a PIII600EB (133 MHz FSB) will I be able to run it at 100 MHz FSB (i.e. 450MHz total speed)?

I know I could do the equivalent with any decent AMD based set up, and I think it *should* work but I don't have much experience of Intel systems. Can any one here confirm if this will work or not?

Thanks guys! :)

alglove
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Post by alglove » Fri Apr 29, 2005 11:42 am

I downloaded the manual from MSI. It *looks* like you should be able to do this through the "Host CPU/PCI Clock" setting in the BIOS. You will not be able to change the multiplier, though.

I can say that I have done this type of thing with other Intel based systems (CPU and chipset), so it depends more on the individual motherboard.

SixToes
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Post by SixToes » Sun May 01, 2005 2:17 am

That's what I think too. I'm going to pick up a cheap one off eBay and see what happens - if it doesn't work I can always sell it back on eBay. I'll post on this thread again when I've tried it.

mb2
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Post by mb2 » Sun May 01, 2005 8:54 pm

you could just get a 600mhz celeron (they are 66fsb).. they use less V than the PIII (ie cooler), and i'd think a 600mhz cel (pIII based) should outperform 450mhz PIII, even with less cache and fsb.. and be cheaper on ebay.

perikooo
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Post by perikooo » Mon May 02, 2005 3:20 am

Hello:

I have done a mod with a broken XBox and an old flex ATX MB that has the FSB at 100Mhz. I have several (5) PIII EBs (133Mhz) that are working happy at ther rated FSB, but refused to work on my 100 Mhz board. The only ones that work there are the PIII 800 EB, not the 667, nor the 733. So if you want to be sure, is better that you buy an 100Mhz Celeron.

Perikooo

SixToes
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Post by SixToes » Mon May 02, 2005 8:18 am

Thanks for the feedback guys! :)
mb2 wrote:you could just get a 600mhz celeron (they are 66fsb).. they use less V than the PIII (ie cooler), and i'd think a 600mhz cel (pIII based) should outperform 450mhz PIII, even with less cache and fsb.. and be cheaper on ebay.
I think it will use slightly more power because it's pretty much the same core (Coppermine vs. Coppermine128) clocked 1/3 faster. Also I thought Slot 1 Celerons were only available with the older Mendocino .25 Micron core, although I guess if I need I could get a slot-to-socket adapter as well.
perikooo wrote:I have done a mod with a broken XBox and an old flex ATX MB that has the FSB at 100Mhz. I have several (5) PIII EBs (133Mhz) that are working happy at ther rated FSB, but refused to work on my 100 Mhz board. The only ones that work there are the PIII 800 EB, not the 667, nor the 733. So if you want to be sure, is better that you buy an 100Mhz Celeron.
Interesting.. any idea what the board was or what chipset it used? It seems really odd that it works with the faster chip, I'd expect it to be the other way around.

I don't really want to have to muck about with a socket adapter, but I guess I can if need be. I'm still tempted to try the PIII and see what happens, but I think I'll start looking out for Celerons on eBay being sold with adapters too. I'll let you know what happens. Thanks again!

perikooo
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Post by perikooo » Mon May 02, 2005 11:39 am

Hello:

The board comes from a broken Intel Dot.Station and is an D810EMO, the chipset is an old Intel 810E.

I think that is just casual that the processor that works is the fastest one, because later, i tried it again with one PIII 866 and does not work.

If you want to be sure, is better than you buy one of the faster Celerons that works on 100 Mhz FSB.

alglove
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Post by alglove » Mon May 02, 2005 1:33 pm

My guess is that the issues with the Intel D810EMO are specific to that motherboard. From looking at Intel's website, it seems that they never issued any sort of BIOS update for that motherboard at all. Also, it is strange that the 667 and 733 would not work at all, since they are clearly on Intel's supported CPU list: http://support.intel.com/support/mother ... 012963.htm . The only thing I can think of is that the 667 and 733 CPUs were of a newer stepping that the BIOS did know what to do with.

By the way, if you want to look up the specs of Intel CPUs (including thermal and power specs), go to http://processorfinder.intel.com/ .

perikooo
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Post by perikooo » Tue May 03, 2005 9:36 am

To Alglove:

I think that the problem is not the board, because i have two of then and both
have the same problem.

There seems to be varios revisions of that board. The one at intel´s site is the newest one, and myne seems to be a bit older because it only supports 66/100 Mhz FSB and not 133 Mhz.

About the bios update. The BIOS on my boards are a hacked one, not an official one. This BIOS supports PIII till 933Mhz, but the hardware can not supply 133Mhz, so here is the problem (or it is possible that there is a bug on the BIOS that prevent some processors to work, how knows).

Thanks for the help.

PS: When i finish my Silent XBox PC, i will post some photos here...

alglove
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Post by alglove » Tue May 03, 2005 2:11 pm

Ah, well. Even if SixToes gets a 600EB and he cannot get it to run at 100 MHz FSB, he still has a fairly cool CPU.

perikooo, I am looking forward to seeing those Xbox PC pictures. :)

mb2
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Post by mb2 » Wed May 04, 2005 7:12 am

SixToes wrote:I think it will use slightly more power because it's pretty much the same core (Coppermine vs. Coppermine128) clocked 1/3 faster. Also I thought Slot 1 Celerons were only available with the older Mendocino .25 Micron core, although I guess if I need I could get a slot-to-socket adapter as well.
you would need an adaptor (v cheap on ebay thou i think).. the cel's like i say use less voltage than the p3 (1.5v compared to 1.65v).. of course if u are underclocking and have voltage controls on the board its not so much of an issue.
there is a 566 and 533(A) cel's which are the same core.. but they use only a tiny bit less power than the 600 so i figured u might want a little performance. make u dont get a regular 533 thou cuz that is mench..undo whatever.. which = p2 based and much hotter.
if ur board only supports 100fsb and u want a p3.. why haven't u considerd a 100fsb p3?

SixToes
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Post by SixToes » Thu May 05, 2005 2:08 am

mb2 wrote:if ur board only supports 100fsb and u want a p3.. why haven't u considerd a 100fsb p3?
Good question - I should have answered this earlier. At the moment this machine has a Katmai PIII 450 which is powerful enough to meet my needs. I've just started running this machine with only one fan (a 80x15 Panaflo 80T-L) in the entire system - in the PSU. It runs fine but is a little warmer than I'd like so I want to put in an equivalent processor which runs cooler. The BIOS options on this board are limited but do seem to allow me to set the FSB to 100MHz which means it should be easy put in a Coppermine PIII600-EB running with FSB at 100MHz instead of 133MHz for 450MHz CPU speed.

The Celeron idea is intersting through. I've just downloaded CPU Power, it states that the Celeron 533A max power is 11.2W and the PIII600-EB at 100MHz is 11.8 - not much in it but the Celeron is slightly lower. So two questions about the Celeron:

1) Is it about the same performance as a PIII 450?
2) The case I'm using is only about 1cm taller than a PIII processor, so would the adaptor fit?

Thanks everyone! :)

SixToes
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Location: London

Post by SixToes » Tue May 10, 2005 3:30 pm

I got the processor today - it won't post at 133 but with the FSB speed selection jumped closed (BTW JP5 is in a slightly different place to where the manual shows it - nearer the CPU socket and rotated 90 degrees, also no identifying text on the motherboard) it works fine at 100. Running Prime95 with the case open it gets warm with the passive cooler, in normal use it stays cool. It should be fine with the case on it normal use, and anyway it has the built in thermal protection.

The next step is to work out what is the max hard drive size it can run when Intel Application Accelerator is installed - I'll try it with my Spinpoint 160Gb and see what happens.

Thanks for your help guys!

alglove
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Joined: Fri Feb 06, 2004 11:21 am
Location: Houston, TX, USA

Post by alglove » Tue May 10, 2005 4:47 pm

Great! Glad to hear it! :)

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