Why would re-seating a CPU cause boot issues?

[Pete.Dakota]

Doing some spring cleaning in the PC, and now after re-seating the CPU (Q8300), I'm getting boot issues. It only boots some of the time; others I get blue screens before or at the Windows logo, sometimes the Windows logo hangs, but sometimes it boots right in and behaves just like normal.

I noticed that before clamping the processor down, it has a bit of wiggle room on the socket - maybe around 1mm in each direction. So it's possible to clamp it down in a slightly different position from before, so could contact pins be an issue? Would a computer boot strangely if the CPU wasn't contacting the socket properly?

I was very cautious taking it out and putting it back in as always. I haven't taken it back out to test yet as it's late and I don't want to be making noise!

 

[Pete.Dakota]

OK, I reseated it. And now it's fine again.

It's pretty hard to explain this 'wobble' within the socket. Imagine you had a square peg in a square hole, and the peg was about 1% smaller than the hole. You're able to move the peg tiny amounts up against each of the walls of the hole, including up into the corners.

What I did was start with the CPU pressed up into one corner of the socket and booted. I got blue screens and it only once got to the desktop before crashing again. I then moved the CPU down into the opposite corner of the socket and booted. No problems. Happy in Prime and no issues at all.

So I'm guessing because this movement is allowed, at the extremes of one of the corners, certain pins aren't connected properly and the processor becomes unstable? Sound about right?

It's really not something that could have been troubleshooted, it was just luck that the first time I installed it it wasn't poorly seated. If I'd had these problems from day 1 I probably wouldn't have thought to reseat the chip.