Hi everyone! My mainboard is D5400XS and my single CPU is Xeon E5420. I want to do some work with dual processor development by adding another CPU. But i could not find to buy another E5420. I found three different CPU (but same family): E5430, E5440 and E5450 from a local saler. I'm not sure about they're both works with my E5420 CPU. Which CPUs can mixing with E5420?
Mixing processors within the same family would not work.
As a matter of fact mixing processors of the model would not work either, if they do not have the same stepping.
So, for multi processor configurations you need to use the same model of processor with the same s-spec (sl code) number or same stepping or revision of processor. This happens since every processor model and revision has a different microcode so the motherboard will require the same version of processor to use such microcode.