Problems with Z170m Pro4s

Here's a ROG guide but you should still be able to interpret what the differences are between you board and the board that the guide is using.

http://rog.asus.com/forum/showthread.php?53306-DDR4-3000-Setup-Guide-For-Rampage-V-Extreme

Meh, IMO all those overnight stress tests aren't needed and may in fact be harmful or at least somewhat harmful to the MB and certainly to your CPU.

If this/was a server I might say sure, but even then not under those amounts of time.

Claf1109 wrote: In the Z170M Pro4s Bios, there's only 2 VCCSA settings : 1.05 and 1.20.

Claf1109, don't worry about increasing the voltage beyond 1.2V if you are using two DIMMs per channel. Intel has always been very (overly) conservative with voltages, particularly with memory.

I'm using two 4GB G.SKILL Trident Z DIMMs rated at 3200, whose XMP profile sets the memory voltage to 1.35V, in my ASRock Z170 Extreme7+ board, with an i5-6600K at 4.4GHz. I can OC that memory to 3800 manually, and the memory voltage is now at... 1.384V.

Your memory is listed in your board's Memory Support list, using two DIMMs per channel. I'm glad to see you are using HWiNFO, can you see your memory voltage in the section with all the voltage data? If so, is it 1.2V?

Do you have a System Agent (VCCSA) voltage setting in your board's UEFI/BIOS? Do you see that voltage in HWiNFO?

You're using two different two-DIMM kits of your HyperX memory. While I have had good luck mixing different kits of Crucial DDR4 memory on my X99 board, it is not a given that unmatched kits of memory will work well together. DDR3 memory is well known to be finicky about mixing kits of the same memory, if the DIMMs were not a matched set.

An interesting test would be just using two DIMMs, one in each channel, and try to OC it to the next level. If that fails to boot, that would indicate you don't have any overhead in the memory's ability to OC. That also indicates using four DIMMs will need voltage tweaks.

My suggestions for using all four DIMMs are:

• Increase the memory voltage to 1.25V, or more, to 1.3V. You won't hurt anything in a short term test, if you are worried about that. If the PC boots at the higher memory voltage, then you can try reducing it 0.01V at a time, if you don't like the higher voltage.
• Increase the System Agent (VCCSA) voltage when you increase the memory voltage. Try about 0.050V more. You may need to experiment with the amount to increase it.
• In the memory timings sections of the UEFI, set ALL of the main memory timings to Auto. That is mainly the timings at the top of the screen, the primary timings. If the PC boots with Auto timings, you may find the timings have increased automatically, which is the intent of using Auto. Use and test the PC with the Auto timings, and if that works, you can then attempt to reduce the timings.
• Skylake boards have a voltage called DRAM Activating Power Supply voltage, which I can see in HWiNFO, and is an option in my board's UEFI. HWiNFO labels it as DRAM VPP. It should be at least 2.500V, mine is shown as 2.560V. If yours is less than 2.50V, you should tweak it up to at least 2.50V.
• My board has a VCCIO option in the Voltages section. Yours does not?

Regarding your CPU OC, your board has a six phase VRM stage, which is good but not as strong as larger, more expensive boards. My board has a 12 phase VRM stage, for example.

Your 4.6GHz OC is 1.1GHz over the base clock of 3.5GHz for our CPU. That is a great OC, expecting more may not be realistic.

What CPU cooler are you using? Skylake processors run cooler than earlier processor in my experience. Skylake processors seem to be more robust regarding the VCore, the stock VID is much higher than Haswell processors. A VCore of 1.4V for Skylake is not excessive for a high OC, given what I have seen other users post on various forums.

The change with Win 10 is odd, I use Win 10 and my 4.4GHz OC is stable at 1.264V. All CPUs are different, you may have had bad luck with the "silicon lottery". But a 4.6GHz OC is certainly not bad at all, it's very good. Expecting more with your board and CPU cooler may be not practical.

What PSU are you using?