Thoughts needed on CPU performance issue

[MattMac2012]

Hey All,

So my hack is up and running, but I've been having this particular issue for a while now, and was hoping to get some thoughts….

Here's my problem...my processor keeps starting out powerful when I first boot the computer, but plunges from approx 3.6ghz to around 1.7ghz or so in the first several minutes, therefore dropping my geekbench/cinebench scores as a result. It won't get me nearly the same benchmark results when I do the tests again, and will continue to stay around 1.7 ghz or so until I shutdown, wait a little while, and reboot.

I can watch the cpu clock drop in the BIOS, and even when I reboot the "About This Mac" will change from 3.6ghz when I first start up, to somewhere between 1.2 and 1.9ghz when I reboot or startup without waiting for several minutes after shutdown.

My guess of what causes this issue is something with the temperature, where I notice according to iStat the CPU temp is within the 50-60 degrees C range when I first boot, but increases to 86-90 degrees C. (It will increase even faster if I start using Geekbench right away) My cooler appears to be mounted right, and came with thermal compound already on it, should I try a different thermal compound?

I also want to note I have no interest in overclocking, but was hoping the CPU Turbo at 3.9ghz would work....

Here the specs of my entire build, which I based off the recommended LGA 2011 build from tonymacx86s site:
- Intel Core i7-3960X
- Gigabyte GA-X79-UD5
- 32GB Corsair 1600Mhz DDR3
- EVGA GeForce GTX 680
- SanDisk Extreme SATA 6Gb/s 120GB SSD
- Corsair Graphite 600T
- Corsair TX850
- Corsair H80 Cooler
- TL-WDN4800
- OSX ML 10.8.2

I hope someone out there can help me figure this out. Thank you in advance!

 

[Rx4Mac]

The processor is slowing down to avoid cooking itself.

Off the top I would say that your cooler is not mounted correctly. You should be able to have temps =< 60° C at full tilt if you are not overclocked. Remove the pump/cold plate, completely clean the old thermal compound off of the processor and the pump/cold plate, re-apply a good thermal compound ( I like arctic silver 5 ) ( about 1/2 of a grain of rice's worth ) and re-seat the pump/cold plate. You might want to make a trial run or 2 of seating the plate after clean off but before re-application of thermal to be sure you have it down. Re-read the directions; watch some youtube videos for this cooler installation and try again. I have used these coolers and they work just fine.

Rx4Mac

 

[MattMac2012]

Thank you for the reply, Rx4Mac! You've definitely helped confirm my suspicions...I will do exactly what you just explained and will report back later this week.

 

[MattMac2012]

So I replaced the thermal compound with arctic silver 5, and made sure 100% that the cooler is on correctly and functioning properly. Still the same issue. I read somewhere else that it could be having certain cpu features enabled in the BIOS, such as speedstep. And since speedstep isn't working with LGA2011 hackintoshes (so I heard) that could be the issue. I'm going to try that out, but any other suggestions or ideas would be greatly welcome. Thanks all!

 

[MattMac2012]

Well, I replaced the cooler entirely with a new H80 and everything seems to be okay....perhaps there was something wrong with the cooler itself? All is well now. Thanks again Rx4Mac!