Sounds fine so far, what is using high CPU when running "slow"??
"It's not beachballing" doesn't define "dead slow".
HDD or SSD?
Hd but as I said in the op, I've already ruled out the hard drive because I put a new one in.
This isn't a general gripe about age or slowly deteriorating performance. This a complete inability to do anything with any reasonable speed.
I agree and I've done all of this with no success. I'm totally stumped because this basically indicates motherboard failure without symptoms that would indicate its motherboard failure.Obviously something is amiss as 300% CPU usage for Kernel is the problem. Normally I would say a software issue, but given you have re-installed OSX on a new hard drive, I would say not. Did you try it with a truly clean install? Just OSX and nothing else. No peripherals plugged in, no other software, etc.
The next thing I would look into is the RAM. Swap positions with the RAM modules. Try them 1 at a time. Try the original Ram modules, also 1 at a time, etc. Good luck!
8gb of ram should be more than enough. The computer belongs to my boss (I'm somehow tasked with fixing it despite not being an it worker). He insists the problem predates the ram upgrade. Maybe I'll dig through my machines and find the same ram to test that too.I was thinking RAM too, have you upgraded? If so try the original, is it recognizing both modules??
Mac book pro early 2011,13" with 8 gb of ram running mavericks. It's running dead slow. I've tried resetting pram, smc, new install and new hd. The CPU is like perma running above 300%. I'm stumped as to what caused it.