ASRock Taichi X99 Vcore increment by 0.005 instead of 0.001 (24hr Prime95 blend)

Hi guys,

I've been out of the computer building loops for a while. Recently the wife nodded so I built myself one.
I'm one of those that must get Prime95 blend test to run for 24hr before I can mark my build complete. As you can imagine this means a lot of tweaking and tuning.

Today I noticed that I can no longer adjust the Vcore by 0.001 increments anymore using the A-Tuning application. When I increase the Vcore in A-tuning, and check the voltage in both HWMonitor and CPU-Z it doesn't move right away. I have to make a few increments (say 0.002 or 0.003) then the voltage on the CPU increased by a whole 0.005V!

Right now I am running the CPU at 4Ghz at 1.250V I believe (yes, can only believe) my golden voltage value was 1.252. I was able to set this voltage at a previous run (got to 15hr52m before a worker died) couple days ago so I don't think I was dreaming. I am almost 12hr into Prime95 blend already now at 1.250V so this might actually be the new and true golden value. But if it's not, how do I adjust it to 1.252???

I attached a screenshot of my system information. You can see A-Tuning Vcore set at 1.249 but the VID is 1.250 (when I change A-Tuning to 1.251 it stays at 1.250 and so on...

Also, does the bus speed always less than 100Mhz? it's bugging the hell out of me too :'(

Thanks for reading!

Sounds like spread spectrum is enabled. I have this board and do not have this issue or notice it at least.

hey Pen, thanks for your reply. It helps a lot .

Regarding my temp... guess I'll take that compliment ^.^. It involves an H115i, 6 high pressure case fans, MINUS both the case panels and the room window in London Winter. Computer is in a very small room so it heats the whole room up pretty quickly without the window open. The In Win case isn't well ventilated for 4 high pressure fans exhaust on the side.

I'm not into overclocking for the sake of overclocking though. I knew I can run the 6800k at 4Ghz stable because that's such a modest overclock from what I've seen so that's what I did. It's stable now (24hr blend yes!). There might come a time when I push the chip harder but at the moment I don't really feel like doing another 24hr run (2 weeks to tweak Prime95 blend to hit 24hr at 4Ghz!) Don't want to go through that again for 500Mhz more.

Rvenger, we have almost identical machine! I would say if you want to run Prime95 for 24hr 1.250vcore is the secret... I can give you my OC BIOS setting if you want as well.
I might try spread spectrum setting to see it if affects the vcore like you said.