Why does diff between core temps increase over time?

[The Rabid Crow]

So after I recently repasted (using the same MX4 and a few times just to make sure it wasn't a one off where I did things incorrectly) I've noticed the difference in temperature between the cores keeps increasing over time.

 

So for instance immediately after repasting if I run Prime95 or playing a game I notice that temp difference between the cores is about 4-5 degrees. However after a few weeks playing the same games or running Prime95... the core temp difference increases to about 10C. This difference doesn't happen at idle when they're 2-3C apart or running light loads - only when the CPU is being stressed...

 

This has happened more than once.... Why does this happen? Is it a problem with the paste? My pasting methods (I've done pea size and spread evenly using a spreader)? Or does everyone see this issue?

[Tan3l6]

3 minutes ago, The Rabid Crow said:

So for instance immediately after repasting if I run Prime95 or playing a game I notice that temp difference between the cores is about 4-5 degrees. However after a few weeks playing the same games or running Prime95... the core temp difference increases to about 10C.

It would be interesting to know whether the higher temp core gets more hot or lower temp core cooler, as the gap increases.

Also - what's the cooler model?

[Haro]

Difference in temps is because the IHS isn't completely flat or because the paste job isn't the best or both. 

What are the temps either way?

[Parideboy]

What @TofuHaroto said. Even most coolers don't have flat coldplates. That's why manualy spreading the paste isn't recommended. It will spread evenly without a manual spread. If it doesn't, it means there's either not enough mounting pressure or paste

[The Rabid Crow]

17 minutes ago, Tan3l6 said:

It would be interesting to know whether the higher temp core gets more hot or lower temp core cooler.

Interesting... I think the lower temps have got lower...

[The Rabid Crow]

Also... I'm not overly worried about the difference in temps (as yet). My question is... why does it increase over time.... what could be causing that?

[Guest]

And the system specs are....?

 

Drum roll.....

[Parideboy]

3 minutes ago, The Rabid Crow said:

Also... I'm not overly worried about the difference in temps (as yet). My question is... why does it increase over time.... what could be causing that?

TIMs have a curing time. Since weeks have passed, you shouldn't see any degradation from now on (till the point where the paste needs to be replaced, of course)

[Tan3l6]

  

1 minute ago, The Rabid Crow said:

Interesting... I think the lower temps have got lower...

My assumption then is, that the thermal paste needed time to get into cracks and crevices of the IHS and cooler base. So the cooling improves?

If the higher temp cores would have gotten hotter, then cooler might be sagging and therefore hanging a bit further from the top. So the cooling worsenes.

 

Just a theory. There might be many other different factors at play.

Also yeah, specs would be nice.

[The Rabid Crow]

3 minutes ago, ShrimpBrime said:

And the system specs are....?

 

Drum roll.....

It's an absolutely state of the art... bleeding edge tech... Lenovo Legion Y520... with a 7700HQ...

[The Rabid Crow]

1 minute ago, Tan3l6 said:

  

My assumption then is, that the thermal paste needed time to get into cracks and crevices of the IHS and cooler base. So the cooling improves?

If the higher temp cores would have gotten hotter, then cooler might be sagging and therefore hanging a bit further from the top. So the cooling worsenes.

 

Just a theory. There might be many other different factors at play.

Also yeah, specs would be nice.

 

It's a laptop and I've tried my hardest to make sure that's not an issue... although the plate maybe imperfect as might be my technique.. I've screwed in across... slowly and tried to make sure I was doing this by applying even pressure at all sides...

[Prodigy_Smit]

5 minutes ago, The Rabid Crow said:

 

It's a laptop and I've tried my hardest to make sure that's not an issue... although the plate maybe imperfect as might be my technique.. I've screwed in across... slowly and tried to make sure I was doing this by applying even pressure at all sides...

Its just a thing that happens. I have the same laptop and as long as the temps don't get worse its fine.