MP 6,1 2013 CPU Upgrade Woes

[MultiFinder17]

I'm having some trouble with upgrading my 2013 Mac Pro. It originally had the 8-core Xeon, and I got a 12-core to replace it with. Upon reassembly, it chimes and boots, but the fan ramps up to full speed and the system is slow as molasses. I tried swapping the original CPU back in and got the same result. Any idea what it's doing and how I can help the poor thing out? Thank you ^_^

 

[tsialex]

Check if the AirPort Extreme cable is fully connected, inspect both sides of the flat cable. If the cable is not connected absolutely perfectly, the Mac Pro slows to a crawl.

iFixit teardown step number 8:

Mac Pro Late 2013 Teardown

After making its debut during the WWDC 2013 Keynote, the reimagined, reformulated Mac Pro finally arrived at iFixit's doorstep. Join us as we turn...

www.ifixit.com

This is the iFixit repair guide for the AirPort:

Mac Pro Late 2013 AirPort Card Replacement

Use this guide to replace the AirPort card in your Mac Pro Late 2013.

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You can also try to run Apple Diagnostics and see any error codes.