Question core stepping

[bcm652]

I have a question for the CPU gurus. I am rebuilding an older computer, MB, MSI 845E-MAX, 478 socket.
MSI manual says that a P4, SL6PF, 2.80G, 478, 533M bus D1 core stepping is what I need.
I tried a P4, SL7PK, 2.80G, 478, 533M bus with E0 core stepping and it did not work.
Identical specs except for the core stepping.
This has probably answered a 100 times on this forum, but I have to ask again. I have been told core stepping isn't a biggy. Why doesn't the SL7PK work for me.
Thanks for educating me.

 

[Roland Of Gilead]

It's possible the bios just needs to be updated for the mobo, to account for the microcode on the newer stepping version of the CPU.It could also be the E0 version is faulty? Have you confirmed it's actually a working CPU?

 

[bcm652]

Thanks for the BIOS upgrade suggestion, already done that and up to date.
The other thing that I should have mentioned, whether it makes a difference or not, the SL6PF is a Northwood and the SL7PK is a Prescott.

 

[scout_03]

fom this list you will see witch cpu your board could handle http://www.cpu-upgrade.com/mb-MSI/845E_Max_(MS-6566E).html

 

[Roland Of Gilead]

fom this list you will see witch cpu your board could handle http://www.cpu-upgrade.com/mb-MSI/845E_Max_(MS-6566E).html

Nice spot @scout_03 . The OP's CPU's are on the list: http://www.cpu-upgrade.com/CPUs/Intel/Pentium_4/RK80546PE0721M.html

So it's possible the CPU is faulty. At OP, did you test it on another system, or had it been working as normal if you've had it for a while?