Puzzling 3770k temp - can you help?

[Damn Dirty Ape]

I'm working with an Asus Maximus V Extreme board and have seen the same problem with (2) different 3770k processors. Both from Microcenter but one in Chicago and one in St. Louis.

The problem is at idle for instance, 3 cores will run around 26-30c and 1 core will run around 10c warmer. I've seen this with 2 different chips, and have verified what I'm seeing with both coretemp and realtemp.

Soemthing up with the board perhaps? It just seems odd that it is shown as being the same core (c0) on both programs.

 

[Vectronic]

That's completely normal, well... numbers out of thin-air I'd say 8% of the time.

Core 1 (or 0) typically gets priority, then Core 2, Core 3, Core 4... so at idle speeds when your CPU isn't doing much, Core 1 is doing most of the work, so it's the warmest.

The reasons why there is such a difference is because:
1. the die is small, and the core is even smaller, most of the chip is taken up by IGPU and L3.
2. The TIM between the chip and the IHS is both poor, and can be un-even, or have bubbles in it.

Typically once you get up to past 50% usage across all cores... Core 2 and Core 3 will become the hottest, because Core 1 is next to the IGPU which probably isn't doing anything so it acts as a miniature heatsink and soaks up the heat... Core 4, is only beside 1 other core... #3... so it has about 66% more IHS to pump it's heat into.

If the core that is hotter isn't Core 1 at idle... you may want to consider de-lidding cause that probably means you have the worst case scenario of already bad TIM.

Normally there is about 5 to 10 degree difference between Core 1 (hottest) and Core 4 (coldest) at idle.

[IGPU][C0][C1][C2][C3]
[-----][------L3------]

 

[Damn Dirty Ape]

That's completely normal, well... numbers out of thin-air I'd say 8% of the time.

Core 1 (or 0) typically gets priority, then Core 2, Core 3, Core 4... so at idle speeds when your CPU isn't doing much, Core 1 is doing most of the work, so it's the warmest.

The reasons why there is such a difference is because:
1. the die is small, and the core is even smaller, most of the chip is taken up by IGPU and L3.
2. The TIM between the chip and the IHS is both poor, and can be un-even, or have bubbles in it.

Typically once you get up to past 50% usage across all cores... Core 2 and Core 3 will become the hottest, because Core 1 is next to the IGPU which probably isn't doing anything so it acts as a miniature heatsink and soaks up the heat... Core 4, is only beside 1 other core... #3... so it has about 66% more IHS to pump it's heat into.

If the core that is hotter isn't Core 1 at idle... you may want to consider de-lidding cause that probably means you have the worst case scenario of already bad TIM.

Normally there is about 5 to 10 degree difference between Core 1 (hottest) and Core 4 (coldest) at idle.

[IGPU][C0][C1][C2][C3]
[-----][------L3------]

Interesting and well illustrated response, thank you. I noticed on our other system just now pretty much the same thing, it is using a 3770k as well.

thanks

 

[Puppies04]

I agree nothing much to worry about although in my experience it is more like 4-8 degrees between the warmest and coolest at idle. I haven't seen a 10°c difference between 2 cores in this situation but it may be that you have background processes sitting on one core making it a little hotter.

 

[TJCS]

Core0 on my 3570K is 10~13 hotter than center cores at idle, and load behavior closely resembles what Vectronic described above.

I re-seated the heatsink 4 times using different TIM spread methods and temps difference were only about 1C? I guess in my case, with such a big variance in temps, something is going on below the lid.

 

[red454]

I had a similar question - here is the discussion:

http://forums.anandtech.com/showthread.php?t=2294093

 

[Ferzerp]

You guys with core 0 the hottest are using the igpu aren't you?

If not, core 2 becomes the hottest.

 

[TJCS]

You guys with core 0 the hottest are using the igpu aren't you?

If not, core 2 becomes the hottest.

I am using a dedicated gpu, and iGPU is disabled in BIOS.

It's interesting looking at IDC's illustration in that thread, because my results are a bit different.

Core0: always the hottest at idle
Core1+2: always hottest at load, but coolest at idle
Core3: Coolest core most of the time, except idle

 

[Ferzerp]

Oh, at idle. I can't read.

You can't put much of any stock in idle temps, they're massively off anyway.