The problem:

My brand new development box (and render target), using a Gigabyte GA-Z97X-UD5H motherboard & Intel i7 4790K processor was showing a strange (read: high) CPU temperature as soon as the processor ramped up to 100%.

When running Prime95, the Corsair Link software (and I backed the following readings up with Speedfan too) was reporting an instant increase to 80 degrees C when using the Blend setting, and a CPU temperature of 100 degrees C when using the Small FFTs (maximum heat) setting. This scared me somewhat! Especially as I was using the Corsair H110i Liquid Cooler – my first time with liquid cooling and at first I thought I’d done something wrong. Like plugged the pump motor into the wrong CPU header. I didn’t do that. No, really I didn’t :-). However…

And the solution:

If you’re running into the same issue, then I’m happy to say that a BIOS upgrade (from F4 to F8) sorted the issue out. CPU temperatures are now reporting at around 26 degrees C @ idle (which is only around 0.5 degree above ambient in our office…) and 65 degrees C when maxing the CPU out using the Blend setting in Prime95. I’m guessing the problem was just a reporting error, rather than the case of the actual CPU temperature hitting 80/100 degrees, but that is a guess.

Incidentally, it’s the first time I’ve used the BIOS on a MB as new as this one, and I gotta say its a dream to use. Mouse & network support, plus plenty of configuration options and a very quick BIOS flash procedure. I like.