Applying thermal compound to processor question

I recently replaced the motherboard on our computer. When I switched the processor to the new motherboard I scraped all the old thermal compound off the top of the processor with my fingernail to read the info on top of the processor. I didn't add any new compound. I figured there was still some on the heat sink pad side. Am I ok, or do I have to go back and add some compound? Thanks. Ed

 

You need to clean the surface of the CPU and the area on the heatsink that contacts the CPU with 90% isopropyl alcohol to remove any vestiges of the old thermal paste. It can break down over time. Then apply a thin coat of your thermal paste to the top of the CPU only, according to the instructions that should have come with the thermal paste. This will ensure proper heat transfer between the CPU and the heatsink.

 

Yea, I was really nervous and thought my computer was going to explode, so I downloaded a program to monitor the temperature. So far so good, the temp was 38C and the computer was on all day. The fan is working well, as I vacuumed the 90% clogged cooling fins when I had the back off.

I ordered a tube of the thermal paste.

 

Job is done. Went pretty smooth. CPU was running cool, but $2 and a little time is worth it for peace of mind.