Since I didn't have any luck with my previous question about unusually high temperatures, lets try bit different one.
I have Ryzen 5 2600X on Gigabyte X470 Ultra Gaming motherboard, with BIOS settings being "Optimized defaults". And on idle, I see it is staying very high on both frequency and voltage. My old i5 6600 would on idle downclock to 0,8Ghz and would have all power saving features on, making it cool and quiet while I work on light stuff. That is not the case with Ryzen. It keeps boosting 3,9Ghz to 4,2Ghz on idle, here and there dropping to 2,7Ghz very briefly, voltages keep jumping between 1,35V to 1.45V, which makes it warm and both if put on graph would look very spikey. Now this wouldn't bother me, if temperature wouldn't also spike between 39C to 54C, making Wriath Spire cooler and exhaust fan I have audibly spin up, spin down, spin up, spin down,.... And overall, I am bit unhappy with how spiky things are, when Intel had this bit better and more consistent. Under load voltage does drop below 1,287V to 1,306V and all cores are around 3,9Ghz, but even in games, temperatures easily get to 70-80C, if game is more CPU intensive. In AIDA64 stress test, it keeps hitting up to 95C. Thought this isn't that big of an issue yet, since that kind of workload is unrealistic for me.
For rest of the system it is:
Gigabyte GTX1070 Windforce
Samsung EVO 750 SSD
2x8GB Crucial Balistix Sport 2400Mhz RAM - I know Ryzen benefits from faster, but due to prices I am keeping it.
EVGA 650W PSU
Antec GX200 case
My questions are, if I can and how can I regulate voltage to limit XFR to at least 1,3V maximum, since under load it drops it bow 1,35V anyway and I feel it is bit too generous with voltage on idle? Or if I can somehow control how aggressive XFR is, beyond just enable and disable? I would rather have it downclock more and run cooler. Sure I don't mind XFR and Precision Boost to be bit more like graphic card, but even those only boost their clock once you load game and not on idle or while doing light stuff. Also is this behavior normal for Ryzen, because it kind of doesn't match what Reviewers say, since they called Ryzen cool chip and great out of the box experience, yet here I am trying to make sense of BIOS, something I never had to do on Intel side.
One thing I did and it helped a bit was to change Ryzen Balanced plan, changing minimum and maximum processor power state from 90-100% to 40-100%. Now at least some cores downclock to 2,2Ghz, shedding off 3-4C. Still it keeps spiking up to 4Ghz+.
Otherwise I would like toknow what voltage should I give it with something like 3,9Ggz. I did bit of testing and on Ryzen Master I got AIDA64 to run more than 30min of stress test at 3,9Ghz at 1,2375v. Which is much lower than XFR gives it at same frequency. Though I never applied it to BIOS. So any good guideline for my motherboard would be appreciated. Also I found it bit odd, or maybe not, if I did only CPU test, it would be stable at 1,1875V, but as soon as I turned it to whole system test, meaning graphic card too in AIDA64, it wouldn't be stable at all. Personally I found it bit odd, because graphic card shouldn't effect it. but it seems like it does on this test. So dunno, if nothing else works, i guess this would at least help.
Also all measurements were done with: