CPU input volt bios setting changing

[BulletApe]

I've got an Asrock z87 pro4 motherboard in my machine and recently added a 4790k.

 

I picked up a tip to help lower temps on my CPU which was lowering the CPU input voltage to 1.7.

 

I tried this and it seemed great while in windows. Even on prime 95 I let it run for 30 min on small fft test and it was ok. Later on doing a bit of gaming I got a reset every now and again. So I thought restore that last change.

 

I changed the setting back to auto in the uefi and save and boot back into windows. It wasn't until I was in the Uefi for something else when I see the setting that I changed to Auto is on Fixed now at a 1.9 setting. I changed it to auto and saved but when I reboot and check it's back on fixed again.

 

Changed it a few times to Auto and it's always back to Fixed next check. Other changes I've made have stuck and they remain unchanged. I don't know whats going on with the setting. Looking at the CPU input voltage readout in 'Asrock Tuning' shows the voltage as around 1.8 bouncing about a bit up to 1.85 or so. Any ideas what could cause the Uefi setting to change itself ?

[Jurrunio]

try reset CMOS a couple of times

 

also, have you finished touching the Vcore yet (the one below 1.4)?

[BulletApe]

Yeah I had settled messing with Vcore at 1.16. Driven mainly to get stable temp.

 

I wonder if it could have anything to do with fastboot in Uefi. Had that enabled. Disabled it now. That setting stuck.