First of all, my system actually works fine (after I worked on getting the vcore the motherboard chose under control manually), and yes, I'm on the latest BIOS, but I'm perplexed by the non-standard behavior of turbo boost on my stock (all "auto") setup with the 4790k and the Z97X-UD5H.
My understanding of Turbo Boost with this processor is that it should boost to 4.4GHz when one (maybe two) cores are loaded, with three cores loaded it would boost to maybe 4.3GHz, with all four cores loaded it would boost to maybe 4.2GHz.
However, even though everything (besides vcore, as I mentioned) is set to Auto, and the BIOS shows the following turbo ratios,
1-core : x44
2-core : x44
3-core : x43
4-core : x42
when I run a stress test that uses all four cores and all 8 threads (either Prime95 or AIDA64) ALL of my cores are boosting to 4.4GHz.
As I said, my temperatures are fine and the system is not unstable, but I can't figure out how to get stock turbo behavior. My understanding is that other brands have settings called "enhanced boost" in their BIOS or something similar, but I can find no such setting in the Gigabyte BIOS. I suppose, I could set all the turbo ratios manually, but I'm mainly just curious why the board, at stock, doesn't behave with Intel-standard turbo boost behavior?