Dual Processor

Some more detail would be nice.

What type of motherboard?

What CPUs have you tried?

Typically, you need to have identical processors.
Check the manual for the motherboard to verify your options and limitations.

Often, you need to either add RAM, or at least install the RAM in a specific manner.

A server class board is where you typically find functioning dual CPU systems.

There are a number of motherboards that have 2 CPU slots, but are either / or.
The old Intel based boards with both Slot 1 and a socket 370 on them are examples of this situation.

Chas

As Chas said you always need to of the same CPU types.But also you can have a Slot 1 and Socket 370 M'Board which will take one or the other type of CPU. A lot of these went into Government buildings when the debate was raging about if Intel would go with the Socket 370 or stick with the Slot 1.

Then if you have a m"board like the Gigabyte GA6BXDU they are a 440 Chip Set and will only support CPU's up to 450 MHZ P111's nothing faster even though they may be Slot 1 and the same speed with a 100 MHZ FSB.

If you have one of the Socket 370 Dual units they could only go to a 1 GHZ Coppermine CPU and they did work quite well.

If you would care to post the make/model of your M'Board I'll see what I can do to tell you how to proceed but a note of caution here if you have one of those Tyan Dual AMD units I've found them to be inherently unstable and will not touch them for love or money.

Col

Same type, same speed.

No

Lee