Normal difference in core temps?

[ZombieJesus]

For a q6600 is a 10c difference between cores normal? two of my cores are 8-10 degrees hotter then the two other cores.....

 

[myocardia]

A 10°C difference at idle means that you don't have one corner/end of your heatsink seated correctly. If you mean a 10°C difference under full load/Prime 95, it's too much, but not unheard of. What are your actual temps? And while running what software?

 

[ZombieJesus]

the difference is greatest under load with prime95 hitting all 4 cores. I'm getting 69,68,59,59 +- 1 degree on the cores got a thermalright 120e on top of it all

 

[myocardia]

If you're running at stock speed, you're way too hot. You know that those Ultra 120 Extreme's shouldn't even be used, unless they're lapped, don't you? I'm not sure what has happened to Thermalright's QC, because they used to ship the flattest heatsinks of any company, but they don't seem to anymore.

 

[ZombieJesus]

running a bit over stock but temps didn't change much.

I think i really do need to lap the sink and why not the core while im at it.

didnt realise how bad the 120s could be

 

[myocardia]

I'd lap just the heatsink first, and see if that doesn't solve your temp problems. It really should.

 

[Griswold]

Originally posted by: myocardia
If you're running at stock speed, you're way too hot. You know that those Ultra 120 Extreme's shouldn't even be used, unless they're lapped, don't you? I'm not sure what has happened to Thermalright's QC, because they used to ship the flattest heatsinks of any company, but they don't seem to anymore.

Wrong. All current Thermalright heatsinks have a convex base because the heatspreaders on Intel CPUs are supposed to be concave.

The problem, from my experience, is that Intels heatspreaders are in many cases so lousy, you might end up with a horribly seated heatspreader or one that isnt concave at the center but somewhere at the edge of the chip. Or in the case of one of my Q6600, the heatspreader is absolutely flat while the other is concave and mates perfectly with a Thermalright Ultima-90, while the former one doesnt and needed to be lapped. To say you need to lap all Thermalright heatsinks due to their QC is wrong.

Here's a quote from Wesley Fink from the AT TR Ultima-90 review (5th comment from bottom):

Thermalright is not alone in advocating convex bases. Swiftech has moved from promoting flat, mirror-finish bases to convex bases with a finish not as good. They call them their bow base and claim 2 to 4C better performance with the "bow".

Engineers have found that the convex base (fat center) mates tighter in the area of the CPU under the cap. Also Intel manufactures caps that are not flat by design - conncave, convex, and wave designs are all used in certain processors. Research shows the convex cooler base mates best with any of these 3 Intel cap types.

The point is this is not a marketing story, as you will see as we go into water-cooling in more detail. Lapping a convex base Thermalright can DROP performance by 2 to 4C.

 

[jmmtn4aj]

Griswold, seriously? How come people have been getting such good results with lapping then?

 

[ginfest]

Ther people who report the "good" or "best" results are those who lap both the HS and CPU as needed. You have to check the how both mate to each other before deciding to lap one or both.
My UE120 has not been lapped nor my Q6600, I checked both surfaces and found very little if any "bow" to either. All 4 of my idle temps are within 3C and my load temps are similar.
So yes, some need lapping, some don't but blanket statements that state a "must do" are misleading.

 

[graysky]

I had some major differences between the cores on my q6600 as well until I lapped the IHS
and also the base of the Ultra-120 Extreme... have a look in those two threads for results. In addition to a 7-10 °C decrease, I also have 1-2 °C difference between cores 0,1 and 2,3... it's totally a function of the concave shape of the IHS and the convex shape of the HS's base.

 

[graysky]

Core temp screenshot after lapping both (loaded with p95 v25.x)

 

[ZombieJesus]

YES!

I lapped both the core and the thermalright 120e and the results are aweseem.

I am now running 3.3 Ghz on my B3 q6600

Well I am sure the engineers thought a concave shape would perform better it appears to have problems for alot of people including me. All my cores are 2-3 degrees of each other now.