Why is my computer running slowly after new heatsink?

How are you gauging that it is slow?

Is it mounted properly? I’ve occasionally goofed, mounted one off-kilter, and wound up overheating.

Then again, if you are flogging Virtual Memory, you are going to be slow anyways; hard drives are no substitute for actual RAM.

But I second @blueiiznh‘s question. Slow comapred to… what? It’s former self? Just slow in general? I mean, the computer I use at work seems slow since it has ¼ the CPU and RAM that I am used to, yet it’s actually operting the same as it did when it was new many years ago.

It all depends on how much memory is being consumed, how many programs are running, viruses, etc.
Starting with memory consummation- if you use too much memory on your computer it will slow down. Imagine a large box filled with various papers. The box is your computer’s memory and the papers are the programs inside. Try searching for a file labeled ‘Stone Sour’. There are tons of other papers and files in there and it would take a while. Try cleaning out your computer’s software every once and a while.

Running Programs- When I first got my used laptop, I found out that there were 64 start up programs slowing down my computer’s operation. Try and disable all of the unnecessary start up programs so it’s not doing advanced calculus when it first wakes up.
Also try not to run many programs at once. When you get done with one thing, close it.

Misaligned Files- This is when parts of a file aren’t where they were programmed in and the computer has to look for them. Like looking for a lost item.

Viruses- Don’t even get me started! You can Wiki this crap.

All in all, get your computer checked out and set up some reliable anti-virus software. By reliable I mean Google it and see what other people thought about it. You may even want to run a thorough virus scan to make sure nothing is amiss. You could set up a few complicated firewalls on your own, too.
Also, listen to the other people on here. They may know more about hardware than I do (like @jerv and his comment about it being mounted properly) , because I know little to nothing about that. I do know the aforementioned things about software and tons on viruses (that’s why you need to Wiki it because I could drone on and on about viruses and malware).
I hope this was helpful because I’m not sure how much you already know so I just typed the things I thought might be useful.

Doing my best to avoid the verbosity train I can only assure you that most speed related issues have nothing to do with the heat in a system. Computers are designed to work under heat conditions.. and if it’s too hot to work.. the computer will shutdown.

I’d wager your problem is closer to a software problem as @BBawlight is talking about.

If I were you I’d run the latest version of CCleaner to delete useless temp files and clean your registry , setup some sort of scheduled defrag and ensure you have enough hard drive space. I would also optimize for performance rather than visual quality. I would examine my event logs , put msconfig into “Selective Startup” instead of “Normal” and uncheck all the useless crap that starts up when you turn your computer on.. and if all else failed.. I’d ask a whole forum full of geeks.

@digitalimpression Part of that “designed to work under heat conditions” is throttling back at high temperatures to cut down on heat production. If the software is the same as it was before the slowdown, it might be a heat issue; if it was slow before, then it’s software.