5C difference between cores??

[jedi940]

I just purchased and installed a thermalright ultra 120 extreme with the s-flex fan. However, i noticed that using tat under load i sometimes get a 5 degree temperature difference between cores. using the stock fan i did not. Under load, core one shows a 5-7 degree drop but core 2 shows a 10-12 degree Celsius drop. Why is there a difference. My thoughts are either the heatsink is not flat on the bottom or that I have too much or to little thermal paste. Anyone else had this problem with any other heatsinks? any suggestions would help. I am thinking about lapping the ultra 120 to see if that solves my problem.

 

[little_scrapper]

My thoughts are either the heatsink is not flat on the bottom or that I have too much or to little thermal paste.

Although I personally would not expecte that much difference in core temps, after seeing my ninja with a razor across it I wouldnt discount anything.
I've never really thought about it but, but how would this affect a quad core?:

Thats a brand new, fresh out of the package, still has the oily residue on it, razor. Notice how the concave is deaper on the right side.

 

[jedi940]

that is a pretty sad difference in height for being right out of the box. It is always core 0 that is hotter. In addition, I get hotter temps using TAT than Prime 95. I am somewhat dissapointed because I am not seeing much difference at all from the stock cooler. I was expecting there to be a big difference. my e660 clocked to 3GHz was hitting 57C. on anandtech.com, they overclocked the x6800 to 3.8 before they hit 50C.

 

[little_scrapper]

I dont use TAT because it gives artificially high temps. Prime95 will give you more realistic load temps. The problem I see with TAT is that because it gives temps that are like 10-15C higher then anyone will EVER see in real usage, no matter how many programs your running, and how many movies your burning at once. People can get all worried and start trying to redude the temps when they really dont need to. For example...TAT was telling me my load temps were like 70-75C. I learned that TAT gives temps 15C too high on allendales. And maybe on ALL B2 stepping or whatever allendales are, and some B2 conroes. So correcting for that problem, I get load temps in TAT of 60C. In SpeedFan and Prime95 my load temps are under 50C(more realistic usage temps) and my gaming temps are about 43-45C. This is of course, after I lapped my CPU and HS which dropped 8-10C off my temps.