#70 Excessive CPU temperatures in 8-core Intel i7

[Anonymous]

Real Temp GT 3.70 reports my Intel i7-4790T CPU core temperatures quickly rising to over 75 degrees C and staying very high when converting WAV files to 320 kbps, 44.1 kHz MP3 files with the Lame MP3 encoder. Selecting 'on-the-fly' encoding doesn't seem to have any positive or negative impact. I am using fre:ac version CVS 20140921 in Win 7 64-bit. The excessive temperature makes it risky to run large batch conversions, particularly on my equipment which is fanless and relies on passive cooling (Cirrus7 Nimbus). Is there a priority or thread management issue here? I notice from software user reviews I am not the only user to report high temperatures during conversions.

[Robert Kausch]

Generally, if your setup cannot stand full load for several hours, you have insufficient cooling. Looking at the Cirrus7 Nimbus, it's obviously a design failure to put an i7 4790T into such a small, passively cooled case.

Your system simply is not designed to take full CPU load for more than a few seconds, maybe minutes. The CPU alone has a TDP of 45W. That just cannot be cooled passively for a longer time.

Thus the problem is not in fre:ac, but in companies putting high performance CPUs in too small cases. You will see the same issues with any other application able to saturate your CPU.

As you are using fre:ac 20140921, you must have enabled parallel processing - otherwise it would use only one of your four CPU cores. Depending on how many cores/threads you allow fre:ac to use, that might put your CPU under full stress when doing large batch jobs. Using the "automatic" setting, fre:ac will use four threads on your CPU. That should not expose cooling issues on any system with halfway sane cooling. If it does, try setting it to use only two threads. If you previously set it to use more than four threads, try reducing that number.

[Robert Kausch]

Searched the net a bit and found an interesting review of the Cirrus7 Nimbus. Unfortunately, it's in German only, but as that system has been sold mainly in Germany, maybe there's a chance that you understand it.

http://linuxundich.de/hardware/der-luefterlose-und-kompakte-silent-pc-nimbus-von-cirrus-7-im-test/

The review is for a Cirrus7 Nimbus with a Core i5-3470T that has a much lower TDP than your i7-4790T. Still it quickly raises to 75°C and then even to 85°C causing the CPU to clock down in that test. The reviewer states that you could probably fry an egg on the Nimbus' surface at that point.

The i7-4790T with two additional cores and its higher TDP will reach such temperatures much faster in a passively cooled setup. It reaching 75°C after five minutes of full load wouldn't surprise me.

As this is a hardware issue, there's not much I can do about it. I'm thinking about adding a configurable temperature limit, though. fre:ac would then use less parallel threads automatically upon reaching the limit. However, this will only be implemented after the fre:ac 1.1 release - if at all.

This ticket will be closed in two weeks.