2600K bouncing temps normal?

[chestnut]

Hey, just got an SB rig up and running, everything stock..BIOS set to defaults, HT on etc.

Temps are fluctuating all over the shop.

For example, at .5sec intervals watching CoreTemp @ idle, all cores are a similar reading..just bouncing everywhere. So if I'm watching core#1 over a few seconds I'll see: 42c, 37c, 40c, 27, 36c, 41c and so on. Dunno if temps are high but it maxed out at 56c under BC2 after half an hour. Does the same thing with RealTemp and AIDA64, though Asus Suite just sits still (like normal) at 28c idle.

Anyone else experience this?

[Falkentyne]

Check for processes using CPU usage. Something using even 1% CPU or even thrashing the HDD can cause temps to change.

[chestnut]

I've just done a fresh w7 x64 install, nothings really been installed other than Windows Updates and the Asus drivers/utils disc.

Even with 1% activity, I shouldn’t see 10-15c jumps in temp (up and down) across each core.

I've made sure the w7 indexer has stopped whilst monitoring.

[unclewebb]

If you are using the C6 sleep state then it's not unusual for the core temperatures to get a little jumpy at idle. C6 lets the CPU switch to 0 volts so the difference in core temperature between that state and a normal C1 idle state can be significant. If your load temps are fine then it's nothing to worry about.

Go into the bios and turn off C3 and C6 and your idle temps won't be as cool but the temps shouldn't be as jumpy either.

[KGB7]

It shouldnt be so jumpy. Make sure the heatisink is mounted properly and you didnt use too much TIM.

My CPU usage is 2% at this very moment and the temps are at steady 28-29c. C3 and C6 are ON as well.

[Johnny87au]

Uneven temps difference between the cores generally mean the mount of the IHS isnt that great so do a remount

[chestnut]

The temp across each of the cores is pretty close, so what I mean is that they're all jumping up and down together. Maybe I've confused people, I’ll update the first post again.

I was actually suspect about my HSF mounting, and that I applied too little paste. I'm using the Noctua paste that instructs you to put a small 4-5mm diameter dot in the centre of the cpu and not to spread it. However I think I only applied about 2mm.

[tentp0le]

Do a couble check on your temps, with HT disabled. Might be smart to reinstall your CPU cooler, but it could also be that the HT is causing the temp differences.

[Johnny87au]

What about under load?? if temps are close under load then i wouldnt worry about it..

[chestnut]

@unclewebb thanks, turning off C3 and C6 helped a lot. They're not jumping as crazy as before, only a little. C1E I left on...so with C3 and C6 off, how much heat does this generally add?

I'm idling looking at CoreTemp now at all 4cores:
core#1 - 43c
core#2 - 43c
core#3 - 36c
core#4 - 36c

Disabling HT didn't affect it anything.

@Johnnyt87au, load temps seem high at stock clocks. After Prime small FFTs for 10min:
core#1 - 63c
core#2 - 63c
core#3 - 61c
core#4 - 61c

I'm going to reapply the thermal paste now.


EDIT: After remounting the HSF it probably dropped temps a couple of degrees but didn't help with the jumping.

I find that after taking unclewebbs advice by disabling ALL C1, C3 and C6 I get the best results...don't really notice any temp jumping now, cheers! Plus Asus Probe is accurate now and gives the same temp reading as CoreTemp.

Load (Prime small FFTs - 10min):
core#1 - 60c
core#2 - 57c
core#3 - 56c
core#4 - 54c

Idle:
core#1 - 44c
core#2 - 37c
core#3 - 36c
core#4 - 35c

Is there meant to be such a temp swing between core1 and core4?

[Johnny87au]

Looking good mate, Idle temps are quite high for stock temps but then again all depends on your ambients.. Seems absoulately fine to me, every quad core ive ran from x58 to 1156 always has atleast 1 core which raises above the rest, Which cooler you using btw? Im guessing noctua from the paste your using hehe

[chestnut]

Ok great, thanks..good to know the cores in most quads vary then.

I had the aircon going, so 23c~...so they do seem high eh, both load and idle @ stock.

I’m using a Noctua u12p. Thinking of doing another remount, even if it's just to see the paste spread, because I don’t see how this Noctua paste can effectively cover the whole (square)cpu after you've applied a 4mm dot in the centre. Made sense using AS with a credit card and spreading it everywhere.

Edit: (although the systems just been built) Is it worthwhile to reinstall w7? Just a fresh install with no drivers/utils/updates..nothing. The second I’m at the desktop, fire up CoreTemp and check?

[unclewebb]

It's not so much the actual core temperature that varies from core to core. What you're seeing is mostly sensor error. Intel designed these sensors only for thermal throttling and thermal shutdown control. They are not 100% accurate for core temperature monitoring. Never have been, never will be. That would cost Intel too many pennies.

Most sensors seem to be +/- 5C but if one reads high and one reads low, the total difference might be 10C even when two cores are running at the exact same temperature.

Glad to hear the C State suggestion worked out for your jumpy idle temps. I thought that's what you meant.

[chestnut]

Interesting, so it's programs like CoreTemp and RealTemp that use these sensors right, and it seems like the thermals will vary from chip to chip, so the next guys 2600K will always be different, kind of like how each one has their own multi-wall?

Intel spec's a Tcase of 72.6c for the 2600K, is this the max safe temp?

Also, if I enable C1/C3/C6 again, my BIOS or Asus Probe reading will drop 10c lower than that of CoreTemp and it will never jump around - which is more accurate?

Sorry to drag this on, I really want to sort this out so I can get stuck into some clocking :P

[Johnny87au]

i'd disable c1/c3/c6 and be happy with the 5c-10c drop... I dont think every chip would yield different temps it really depends on how much vcore/HT and ambients you have which take place in how much Temps your gaining..