i7 4790K@4.4Ghz + Noctua U12P SE2 - Temps acceptable under these conditions?

[LunyAlex]

So I recently built a new rig with an i7 4790K in it.

I expect this rig to last me for quite some years, so I'd like to make sure it's operating within safe "happily ever after" parameters.

During initial tests the CPU was running quite hot.

With Turbo Boost Enabled we're talking up to 74*C in Crysis 3 (Those pesky Hyperthreaded tall-grass areas) and upwards of 85*C in Intel Burn test [Since then I've learned that Prime95 2.66 is the way to go for stress testing new Intel CPUs (?)].

What I noticed, though, was that the CPU was getting a lot of volts. HWMonitor was showing sustained 1.28V under load.
So I went into my Mobo's Bios (Gigabyte Z97-D3H) and played with the VCore Offset and LoadLineCalibration settings.

After getting a few BSODs (low Vcore) I got it stable at a point where it never goes beyond 1.188V.

Now the temps are:

(@4.4ghz [Turbo Boost])

30-32*C Idle.
Peaked at 64*C while gaming (Battlefield 4 and Crysis 3) but average temps were more like 55-62*C.
Peaked at 74C in Prime 95 v2.66 but mostly stayed within 70-72*C.

My Ambient temperature is on the hot side (~28-29*C) and my case has 1x120mm and 1x200mm fans on it.

Would you say these temps are okay for prolonged use?
Does the fact that I had to undervolt the CPU to get these temps sound like cause for worry (faulty unit)?
Would you feel comfortable running the CPU at these temperatures?

Sadly I'm very nervous about reapplying thermal paste because of a... negative past experience, but if push comes to shove I'd be willing to try it that.

Any thoughts on the matter would be strongly appreciated.

 

[CompuTronix]

LunyAlex,

Was your Prime95 test performed with Small FFT's?

Prime95 version 26.6 Small FFT's is the proper test for "thermal testing". 10 minutes is adequate. For "stress testing" a minimum 8 hours is necessary for P95 Small FFT's as well as Blend.

Also, any and all varieties of stress testing utilities, games and apps may be used to verify stability.

Intel's Thermal Specifications are based on 22C, which is Standard Ambient and "normal" room temperature. Since your ambient is 6 to 7C above the standard, you must subtract that 6 or 7C from your results in order to have a meaningful comparison to Intel's specs. This would make your corrected Core temperatures only 68C, which is excellent.

Core temperature is 5C higher than CPU temperature due to sensor location. Intel's Thermal Specification is "Tcase", which is CPU temperature, not Core Temperature. Tcase for the i7 4790K is 74C. Tcase + 5 makes the corresponding Core temperature 79C. This is the spec for your processor.

This means that your Core temperatures corrected to 22C ambient are 11C below spec, while your actual temperatures are still 5c below spec, which is excellent due to your low Vcore.

The relationship between Core temperature and CPU temperature is not in the Thermal Specifications; it's only found in a few engineering documents.

Please read this Tom’s Sticky: Intel Temperature Guide - http://www.tomshardware.com/forum/id-1800828/intel-temperature-guide.html

Thanks,

CT

 

[LunyAlex]

LunyAlex,

Was your Prime95 test performed with Small FFT's?

Prime95 version 26.6 Small FFT's is the proper test for "thermal testing". 10 minutes is adequate. For "stress testing" a minimum 8 hours is necessary for P95 Small FFT's as well as Blend.

Also, any and all varieties of stress testing utilities, games and apps may be used to verify stability.

Intel's Thermal Specifications are based on 22C, which is Standard Ambient and "normal" room temperature. Since your ambient is 6 to 7C above the standard, you must subtract that 6 or 7C from your results in order to have a meaningful comparison to Intel's specs. This would make your corrected Core temperatures only 68C, which is excellent.

Core temperature is 5C higher than CPU temperature due to sensor location. Intel's Thermal Specification is "Tcase", which is CPU temperature, not Core Temperature. Tcase for the i7 4790K is 74C. Tcase + 5 makes the corresponding Core temperature 79C. This is the spec for your processor.

This means that your Core temperatures corrected to 22C ambient are 11C below spec, while your actual temperatures are still 5c below spec, which is excellent due to your low Vcore.

The relationship between Core temperature and CPU temperature is not in the Thermal Specifications; it's only found in a few engineering documents.

Please read this Tom’s Sticky: Intel Temperature Guide - http://www.tomshardware.com/forum/id-1800828/intel-temperature-guide.html

Thanks,

CT

Hey! Thanks a lot for the swift reply!

Prime95 Version 26.6 Small FFTs is indeed what I used. Ran for 30 minutes.

I'm quite happy to read the word "Excellent" repeatedly, hah. I'll stop worrying then.

Thanks again and thanks for the Intel Temperature Guide link. Very insightful.

Have a good day!

 

[CompuTronix]

You're very welcome. I'm glad that I could help.