A question about replacing backplane board

[c1830]

Hi guys.
My Mac Pro early 2009 (8 core) had upgrade firmware from 4,1 to 5,1.
(but the CPU is still E5520.)

2 month ago, the backplane board is not work (the backplane board shows "631-1009").
I would like to buy a new one from eBay.
so, I have to buy a "631-1009" backplane board to replace the old one, right?
if I buy "631-1427", can it work?

Thank you.

 

[scott.n]

Part 631-1427 is the backplane board for the 2010/12 Mac Pro.

Your 2009 MP will be functional with that part, but your fans will run at full speed due to the SMC version mismatch (with your processor tray).

You should replace with 631-1009 if at all possible.