What could be causing these temperature spikes?

[BlackHoleBox]

Corsair H110 on an i5 6600k. When I first built this system all four cores idled around 15-17C and Prime95 would have to work hard to push it over 30. During a recent bout of in-depth troubleshooting, I removed all components in an effort to simplify the process of elimination.

Anyway, since putting everything back together, my CPU temperature readings have been acting strangely. Sitting at the desktop, core 1 will be at 19C then jump to 31C and back with performance monitor reporting no CPU usage. Even fast scrolling through a page will increase temps to 30+. It never did this before. I have so far removed the pump, cleaned all surfaces with 91% isopropyl, and reapplied thermal paste four times with no change.

 

[faalin]

What software are you using to monitor your temps? and what is your temp in your room? I have a feeling you have a bad prob or the software is reading something wrong.

Your room by its self would have to be in the mid to low 50*f in order for that H110 to give you 15-17C (60*f) temps

 

[dangus]

hmmm prime 95 not causing the CPU to go over 30C seems really really low no matter what clockspeed/voltage you are running. the lowest ive ever got my 4770k to run at at idle is about 25C. mild usage/web browsing sees temps run around 30-40C. you're just fine. i really think faalin is correct that you were getting bad readings the first time around.

 

[BlackHoleBox]

Room temperature is 20C. I use Gigabyte's SIV utility as it's the only monitoring software I have found that reports the same readings as the BIOS.

 

[Ecky]

You can't have a processor temperature below the temperature of the air around it.

 

[faalin]

no air or water cooler can be below room temps by themselves, it is just impossible. I have seen the use of peltiers with waterblocks used to chill the water below room temps, but now your going to extremes.


I would try downloading core temp or HWmonitor to see if it get you different temps

 

[dangus]

regardless...30C while scrolling and web browsing is completely normal. im not sure what we're expecting here

 

[BlackHoleBox]

It seems the point was missed as the "Uhm, actually" squad stopped by to be unhelpful. It's my fault for trying to include details pertinent to the issue.

But no, the temperature jumping 10+C while sitting idle - staring at perf monitor with no activity - is not normal.

 

[Ecky]

That's pretty normal, really. The sensor in modern Intel CPUs is much closer to heat-producing components than on AMD CPUs and older Intel chips, so even tiny changes in activity (a few percent) will show up as rapid changes in temperature. The farther away from the hot parts you're measuring, the more "buffered" the temperature changes are.

 

[dangus]

It seems the point was missed as the "Uhm, actually" squad stopped by to be unhelpful. It's my fault for trying to include details pertinent to the issue.

But no, the temperature jumping 10+C while sitting idle - staring at perf monitor with no activity - is not normal.

it's absolutely 100% normal. i've seen that activity in the following CPUs ive owned over the past 5-6 years: pentium g860, i5-2400, i5-2500k, i7-3770, and i7-4770k. on all those CPUs i have never seen any temperatures below 20C at idle. probably more like 25C at idle. if you can get a CPU to idle at 15C then you are doing something incredible to the point of delidding your cpu and using that liquid pro TIM stuff. my 4770k is running at 30C-37C while writing this post. 5-15% load and the ambient temp is probably about 20C in my room. perfectly fine you really have nothing to worry about.

P.S. - a 6600k running even at stock settings at 30C on prime 95 with an h110 would be immensely impressive and i'd love to see it.