Upgraded to Win7 Pro x64 from Home Premium x64 (Anytime Upgrade online), specifically to add second identical physical dual-core Xeon processor. BIOS only shows one CPU in socket 0. Win 7 Pro only shows the 2 original cores.

Per recommendations on a Microsoft forum, I used MSCONFIG and EasyBCD v2.2 to "force" Windows to look for more cores... nada!

Mobo BIOS will not "see" second processor, at all. Only recognizes one in either socket. (I have tried both now.)

Dell docs and forums insist the mobo is dual-socket supported in "Pro" and "Ultimate" versions of Windows.

Replaced mobo and running latest Dell BIOS (A08) to no avail...

Two tubes of thermal paste and two mobo's later and I'm outta patience.


  • If bios doesn't see it then this isn't a Microsoft problem – Ramhound Feb 12 '15 at 1:13
  • It could be a bad power supply, have you checked to power going to your CPU's? – Michael Feb 12 '15 at 1:44
  • I can run either identical processor in either socket, just not both at once. BIOS will show either CPU in either socket. – ToddE207 Feb 12 '15 at 3:50
  • I do not have the tools/skills to test the actual voltage going to each socket. However SiSoft sees and benchmarked each CPU with almost identical results. Stumped. – ToddE207 Feb 12 '15 at 3:53

It has to be a power supply problem. I had the same problem until i replaced the power supply with Dell part# U9692. My system/BIOS now sees both processors. Hope this helps! Steve

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