does dual cpu sys have to be the same cpu?

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Limp Gawd
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Aug 1, 2004
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ive been wondering if you run a dual cpu system to they have to be the same model cpu?
 

FLECOM

Modder(ator) & [H]ardest Folder Evar
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short answer, yes

long answer... meh, pretty much yah, there are a few people who have modded the multipliers on one cpu to match the other, you could do that... but really, you want them to be the same for stability etc
 

dagamore

Gawd
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Oct 25, 2002
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basicly yes.

can you runn diff steppings on some systesms yes

could it cause issues yes

will it cause issues, dont know

i ran a xp2200+ and an xp2100+ both with the l5 mod, and hard changed to 2400+ chips for 2 years with out any problems in a tyan dual MP board.
 

[H]EMI_426

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If you're talking about just PC/x86-type hardware, yeah, generally your CPUs have to be pretty similar. However, once you get away from x86 hardware the field is much more open...I've seen SGI boxes with several different-speed CPUs in them...Or was that SGI? I can't remember any more...I know that once you stop playing with consumer-grade hardware things get a lot more interesting.
 

relic

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As Hemi said; in x86 you are technically supposed to match CPUs.

In reality many motherboards run completely stable with different speed/voltage/steppings CPUs installed.

There is a problem, however: Noone supports this, so if you have a problem, noone can help you.
 

Steel Chicken

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relic said:
As Hemi said; in x86 you are technically supposed to match CPUs.

In reality many motherboards run completely stable with different speed/voltage/steppings CPUs installed.

There is a problem, however: Noone supports this, so if you have a problem, noone can help you.

this the most acurrate answer
 
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Jun 11, 2000
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Filter's answer is pretty accurate. Once upon a time, there were people found a way to run a Pentium II with a modded and overclocked Celeron (I think the mod was to make the Celeron SMP-enabled via the PCB and bump the FSB from 66MHz to 100MHz). Of course, that was a long time ago and the Celeron back then was pretty much a PII with some cache disabled.

Things have moved along significantly since and if you choose to try it, you're pretty much on your own. ;)
 

CrazyRob

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Not that i recommend it, but i do remember an instance not long after the release of the original athlon mp's. One review got his hands on a pair of 1.0's and 1.2's and just for grins, booted a board with a 1.0 and 1.2, not only did it boot fine, but it also benchmarked between the 1.0 and 1.2 systems with smp intensive apps like 3d studio max. their motivation to test was because of the fact that each cpu was supposed to have it's own bus to the memory, so in theory should have worked fine, and aparently it did.
 

ambit

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I've run Katmai pIII 450's with CuMine 550's and 600's in a Giga-Byte dual slot1 board.
The BIOS would report the clock speed as slightly over whatever was in cpu slot 0. Like 485Mhz.. wtf.. ?
Worked without any problems.
 

XeonTux

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Aug 29, 2004
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Well if you are buying procs you should try to get matching steppings.

If you're building something out of spare parts ya just try whats handy, if it works it works, if it doesn't it doesn't.
 

[H]EMI_426

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XeonTux said:
Well if you are buying procs you should try to get matching steppings.

If you're building something out of spare parts ya just try whats handy, if it works it works, if it doesn't it doesn't.
Or you can just look at the Intel docs on running CPUs in multiprocessor setups...The docs will generally tell you what steppings (of the same speed CPU) work together and what don't. You'll only run in to problems with faster PIIIs and such, though.
 

Yoblad

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What about different cache sizes? Like a Xeon with 1M cache and another with 2M cache.
 

XeonTux

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Then only 1MB of the 2MB CPU would be used. It may be best to install the smaller cached CPU in the first slot/socket, not too sure if it really makes a diff tho
 

xxGriff

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ok its an old thread, but i have been playin with a SuperMicro P6DBS and some slot 1 PII/III's

according to intel as long as your cache does not exceed 1mb, you can mix steppings, and speed*

that said, the fatser CPU will need to be Clocked the same as the slower CPU is what Intel says.

I have a matched pair of PII-450's-Deschutes, and took one out, replaced with a PII-300-Deschutes, ran fine @300(for 300mHz anyway). i was able to get 450mHz using these 2, but had to up some voltages to get the 300 stable, not much +0.2v

I wondered about mixing 450-Deschutes with a 450-Katmai...

would SSE enabled/disabled or sent to the PIII? I dunno...
 
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