This is my first PC build, and I removed the CPU to replace the motherboard after discovering that some socket pins were bent. I then noticed quite a bit of excess thermal paste and a tiny mark on the CPU's contact pads. I'm not sure whether the mark is residue, a scratch, or something more serious, and I'm already worried because the system has been difficult to get booting. Should I be concerned, and what is the safest way to clean or inspect it?
3 Answers
If the system boots after cleaning and installing everything correctly, run a CPU stability test and monitor temperatures. A failed boot by itself doesn’t prove that the CPU suffered overvoltage damage; that conclusion would require clearer symptoms or testing.
A small mark isn’t automatically evidence that the CPU is damaged. It could be leftover paste, normal contact wear, or a minor surface mark. Clean the pads carefully, inspect them under good lighting, and test the CPU in the replacement motherboard. Bent socket pins can cause boot problems, so the motherboard may be the main issue rather than the processor.
If any thermal paste got onto the underside of the CPU, gently clean it with 70% or higher isopropyl alcohol and a clean, soft cotton swab. Use plain alcohol without aloe or other additives, don’t scrub aggressively, and let the CPU dry completely before reinstalling it. You may need several swabs rather than applying more pressure.

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