On my Maximus Hero VIII, my VCCIO voltage was ridiculously high when set to auto after setting XMP (1.35v or so), so I tried to set it to a more reasonable 1.15v. Booted into windows.. 1.008v. Tried a million different settings, higher, lower, doesn't matter, booted into windows, and it's once again stuck at 1.008v. Nothing sticks. When it was sky high at 1.35v, it did show 1.35v in Windows, so I don't think it's just a matter of the voltage not being displayed properly, unless it's only not displayed properly if it's under 1.35v or whatever it was set at.
If I set it back to Auto it just goes back to.. 1.35v in the BIOS and in Windows, which is way too high. The BIOS *does* show that it's at whatever I set it at when I'm in the BIOS, but not in Windows. I don't understand what exactly is going on here that would prevent this change from sticking when set manually, but going sky high when set to auto. Is there an option I have to adjust to force the manually set VCCIO voltage from actually sticking? Using the latest bios (3802) of course. Done plenty of searches on google and on these forums and I haven't been able to find anyone with this issue. I have some new ram coming tomorrow and I'm extremely frustrated with not being able to manually set the VCCIO voltage at all.
edit: I've also tried using AI Suite 3 to adjust the voltage. It doesn't seem to work either. I can adjust the SA voltage and see it go up and down in HWMonitor or OCCT or wherever else, but VCCIO just doesn't budge.
edit: Okay, things are getting weird. I'm also an idiot, but I'm not. I haven't touched my settings or messed with voltages for awhile, but I was under the assumption that VTT = VCCIO/IMC voltage. There are posts like these (https://hardforum.com/threads/voltage-difference-between-cpu-vtt-and-ram-voltage.1924296/#post-10428...) that calls VTT the IMC, and VCCIO is also the IMC. Confusing, right? I was definitely confused. I did find out that adjusting VCCIO voltage adjusted what was listed as the IMC voltage. I was looking at VTT in OCCT the entire time, so my VCCIO voltage adjustment is working fine.
That brings up another question--why did I think that VCCIO in my BIOS was supposed to change the VTT voltage modifier in OCCT, and not the IMC? Because when VCCIO was set to Auto, VTT reflected the same voltage as VCCIO was reading in the bios. What the hell is going on here? When manually setting VCCIO, VTT goes back down to 1.008v, and doesn't budge. Why was having VCCIO set to Auto also adjusting VTT? I'm still very confused here, because I don't know what the hell VTT is even showing. It's not DDR4 VTT, as that's set at like 0.65v, so what is it, and why was it identical to VCCIO voltage when voltages were set to auto? I solved my problem, but I'm very confused. AI Suite shows PCH Core Voltage at 1v, and CPU Standby Voltage at 1v, is it either of those? Why would having VCCIO set to Auto change either of those? It's labeled as "VIN6" in HWMonitor. Can anyone explain what VTT is, and why it's voltage was the same as the IMC with Auto, and then magically back to 1.008v when I manually input VCCIO (IMC) voltage?