10 degrees difference between cores

[Funtoink63]

Hello,

 

I'm replacing CPU on my HP Compaq 6820s laptop. After updating BIOS, taking it apart and replacing CPU, I found that the new CPU does have different temperatures between cores. And not just 1-2 degrees like the old one. Its whooping 10 degrees. I tried add little more paste - nothing. Repaste it once again - nothing. Core 1 - 30 C, Core 2 - 40 C. That's just an idle, I didn't tried stress test because, well.. I just forgot to try them before taking it out and sticking in old one. I was about to give it another try when I noticed that the die has a scratch on it. Now, I'm hesitating to try it again or call the guy whom I bought it from.

 

What could cause of the large difference between both cores? Could it be that scratch, is it dying or I'm just doing something wrong?

[RGProductions]

5 minutes ago, Funtoink63 said:

 

Stress test it, see if it works. 10 degrees is okay, as long as the hottest core is still reasonable. That scratch is not good, but might not affect this.

[Guest lilbman]

It's most likely the heatsink.  It's not laying evenly across the CPU.

[Funtoink63]

26 minutes ago, RGProductions said:

Stress test it, see if it works. 10 degrees is okay, as long as the hottest core is still reasonable. That scratch is not good, but might not affect this.

The thing is, I stripped a little bit of the other 2 screw that hold GPU part of the heatsink.

Spoiler

While they doesn't look special (standard Philps screw +), I don't know if I have any substitute / similar to to it. It doesn't resemble + that much anymore, meaning that I can tighten in (maybe) ´2 more times before they get completely strip out.

19 minutes ago, lilbman said:

It's most likely the heatsink.  It's not laying evenly across the CPU.

I tried old CPU in the same condition like the new one and the difference was like 1-2 degrees (idle). Also, all 4 screws that hold CPU part of heatsink have little springs under it. Meaning I can't really tighten one side more than other because the spring won't let me.

 

[Funtoink63]

Update:

I did tried to stress test it.

 

Old CPU:

idle: C1 - 40~45, C2 - 42~47

load: C1 / C2 - 65

 

New CPU

Idle: C1 - 30, C2 - 37

load: (OCCT) C1 - 46, C2 - 54

         (Prime95) C1 - 52, C2 - 56

 

After 15 min, HWinfo in both tests froze, task manager UI was broken (black bars) and heat pipe above both GPU and CPU was rather unpleasant to touch (quite hot). Both tests were done in "open air" style (i.e. motherboard sitting on desk). Unlike previous attempts, this time I tightened each one screw to half point and after all 6 screws were like that, fully tightened them. It looks like did something because the temps are little less drastic (7 degree difference compared to previous 10).