There are four essential determinants of compatibility when
upgrading a CPU these days:

1.  FSB - Front-Side Bus speed
  The Celeron is designed for a 66 MHz FSB.  Mainline P2/P3 CPUs
typically use a 100 MHz FSB, and some of the newest use a 133 MHz
FSB.  Odds are good that your motherboard supports both 66 and 100
choices, switchable either in the CMOS config or via a jumper.

2.  Clock multiple
  These days, this is usually locked at the factory.  Clock multiple
times FSB yields clock speed in MHz.

3.  Voltage
  Faster versions of the same CPU typically produce more heat; newer
versions often counter this by running at lower voltages.  The
voltages that your motherboard can supply may limit your ability to
plug in the latest CPUs -- but see below.

4.  Socket/Slot
  Celeron/P3/P4 chips have come in a variety of shapes/sizes:  Slot
1, Socket 370, flip-chip.  If the faster CPU you want comes in a
different form than your motherboard can take, you may have two
choices:  a new motherboard, or an adapter to mate the new chip form
to your motherboard.  These adapters may also include voltage
regulators to address #3 above....

  In general, the list of CPUs supported by a motherboard tends to be
current when it is produced, but go out of date.  For instance, I
have a PII board that has jumpers to go up to 600 MHz.  But the
manual say PIII-550 is the fastest CPU that will work, and research
suggests that this may only be true for *old* versions of the 550MHz
PIII -- newer ones specify a voltage my board doesn't offer.

David Gillett
A+, MCSE, CCNA, unemployed


On 31 May 2001, at 20:57, Kevin Scott wrote:

> I have a intel celeron 400mhz processor.  I want to upgrade my
> motherboards cpu. I would like to upgrade to a 600mhz or 700mhz.
> How would I find out if my motherboard will be able to handle a
> 600mhz or 700mhz cpu or even if I am able to upgrade this
> motherboard at all.  What would be the first steps to take.  If I
> am able to upgrade my motherboards cpu to a 600mhz or 700mhz. What
> would be the steps to take to install the new cpu is this a
> difficult process. Any help would be greatly appreciated.
>
> Kevin Scott

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