cpu vcore throttling back to 0.900V when stress testing

[Steamwhistler]

Hello all,

     I have a gigabyte ga-990fxa-ud3 (rev 4.0) with a XSPC watercooled fx 9590. the issue i am having is the the cpu vcore will be stable at 1.512V for 15min or so using prime95 and drops to 0.900V as soon as the cpu temp hit 40`C. it is very slow climb up to 40`C. as soon as the voltage drops to 0.9V the cpu temps drop back to 30`C  i have disabled cool and quiet, cie, c6, svm etc. i have disabled cpu boost and adjusted the multiplier up to 25.00 to give the cpu the base of 5ghz. nothing crazy in the sense that that is the advertised speed. Is there something in the bios i am missing to stop the voltage drop? the cpu is listed to work with this motherboard so i'm assuming its something i'm missing. i should also add that i'm using a 650watt psu and i have a gtx650 (until after Christmas  )

Any thoughts?

Thanks

[autotech]

Have you turned of LLC which is load line calibration.

[DigDeep]

Maybe your VRM(mosfets) are overheating or NB

[wah007]

I had throttling but it always throttled and not after a certain time. Turning off APM in the BIOS fixed this. Yours could be a overheating issue.