A2B-D Can you use Dual Processors of Diff Speeds?

  • Thread starter Thread starter Al Franz
  • Start date Start date
A

Al Franz

Putting together a system with spare components laying around on an Asus
P2B-D board. In the manual it states you have to set the jumpers a certain
way depending on the Internal speed of your processor. If you have dual
processors do they have to be of an idential Mhz. Can I put a Pentium II
350 and 450 Processor on this board? The jumper settings are different for
each?
 
Al said:
Putting together a system with spare components laying around on an Asus
P2B-D board. In the manual it states you have to set the jumpers a
certain
way depending on the Internal speed of your processor. If you have dual
processors do they have to be of an idential Mhz. Can I put a Pentium II
350 and 450 Processor on this board? The jumper settings are different
for each?
Click to expand...

Generally you "can" run two different CPU's but they must have the same FSB
and multiplier. Effectively you will be running the PII-350 normally and
under-clocking the PII-450 to the same speed as the 350 (ie, same FSB and
multiplier).

If the 450 is multiplier locked and you need a non-standard multiplier to
under-clock it, you'd better break out the soldering iron and razor blade
to unlock it. Google is your friend here.

Ideally you should run two identical CPU's but your setup *could* be coaxed
into life.

Good luck,

James
--
Fortune cookie says:
BOFH excuse #398:

Data for intranet got routed through the extranet and landed on the
internet.
 
Al said:
Putting together a system with spare components laying around on an Asus
P2B-D board. In the manual it states you have to set the jumpers a certain
way depending on the Internal speed of your processor. If you have dual
processors do they have to be of an idential Mhz. Can I put a Pentium II
350 and 450 Processor on this board? The jumper settings are different for
each?
Click to expand...

You won't damage anything by trying that combination, but I don't think
it's going to work :-(

The multiplier jumper settings are irrelevant since both processors have
locked multipliers and will ignore the jumper settings. Set the FSB
jumpers to 100Mhz as that's correct for both processors.

I just tried a similar experiment here on a P2B-DS (same board, just has
the Adaptec SCSI chipset locations populated), with processors I had
available:

PIII-S 1.26Ghz & PII 400
PIII-S 1.26Ghz & PIII 450
PII 400 & PIII 450

In all cases the board posted and detected two processors. The BIOS
reports the CPU speed and type installed in the slot closest to the
memory (I tried each pair both ways - the PIII-S posted at 950Mhz
because the FSB was set to 100Mhz). In all cases XP started to boot, but
the system reset at the point the first graphical screen would normally
be displayed.

Mixed CPU speeds didn't work for me, YMMV :-)
 
Thanks for the help on my initial question. Another one deals with hooking
up the 2nd fan for the 2nd processor. I see 3 connections that look like
FAN connectors on the motherboard. They are labeled CPU_FAN, PWR_FAN, and
CHA_FAN. I assume CPU_FAN would be for a fan on one of the processors but
what do you hook the 2nd processor to? What are PWR and CHA fan's, are
those if you have additional fans in the case?
 
Al said:
Thanks for the help on my initial question. Another one deals with hooking
up the 2nd fan for the 2nd processor. I see 3 connections that look like
FAN connectors on the motherboard. They are labeled CPU_FAN, PWR_FAN, and
CHA_FAN. I assume CPU_FAN would be for a fan on one of the processors but
what do you hook the 2nd processor to? What are PWR and CHA fan's, are
those if you have additional fans in the case?
Click to expand...

For reasons known only to Asus, they labelled the three fan connectors
the same way on both single and dual processor P2B series boards.

CPU_FAN is for the first CPU (closest to the i/o connectors)
PWR_FAN is intended for monitoring a power supply fan if the supply
provides that option.
CHA_FAN is intended for a chassis fan.

You can use either PWR_FAN or CHA_FAN for the second processor, PWR_FAN
is the obvious choice as it's much closer to the processor slot.
 
DaveW said:
You have to use IDENTICAL processors.
Click to expand...

That's incorrect.

If you research the issue at intel.com, you will find that Intel states
they do nothing to prevent mismatched processors of the same family from
operating correctly in an SMP system, but they only validate selected
combinations.

Intel publishes tables detailing exactly which mismatched processor
combinations have been validated. Typically, they validate processors
with matching FSB and multiplier specifications but differing core
steppings.

P2B
 
Back
Top