having some issues with p4s333

Hey guys I am having some issues with my buds board. he had a willy 1.6 and was upgrading to a 2 ghz northwood. I got the latest bios the 1006c and the cpu didnt post at all everything powered up but now post. I put the 1.6 back in and it posts and boots up fine. Then i take the 2 ghz cpu and put it on a bd7 raid and It boots up and posts fine. What do you all think the issue is. The chip is fine but it just having some issues posting on the p4s333 and i know theres gotta be something for me to do to fix the issue.

morning bump.

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Are you positive the 2.0a is seated correctly? My buddy brought over his 2.0a to put in my P4S333 to see how high we could get it. When I put my 1.8a back in it wouldnt post. I was like wtf. I pulled the chip out and reseated it and it worked.