Just finished building my watercooled rig last week and I found some interesting results that raised a few questions for me...
First off, my parts and my loop:
Crosshair V formula (Non-Z)
AMD 8350, 4.7GHz @ 1.48125V
R9 290X, 1115 Core and 1450 Mem @ +50mv
CoolerMaster Silent Pro Gold 1200W
240GB & 256GB SSD
2x 500GB HDD
EK 140mm Res > D5 @ Setting 5 > 360MM EK PE Series Rad > EK Supremacy > 120MM EK PE Series Rad > EK 290X Block w/Backplate > Res
I've been testing for the past couple days using games and benches (Heaven, Valley and 3DMark) while using MSI AB to monitor Core/Mem fluctuations.
After thorough testing, I've found that the core will throttle after 50mv. Temps are NEVER A PROBLEM (45c Core, 50c VRM1 and 42c VRM2) so I have no idea why it would throttle.
I double checked the seating on my card, made sure that the VRM's had contact with the thermal pads to the block... basically the install was perfect.
I tested by using the same clocks above, power limit maxed at +50 and running extra voltage at 50mv and 56mv. While playing games and running benches, the core didn't stay rock solid @ 1115Mhz on +56mv. I dipped as low as 25MHz sometimes. I know its a rather small number but its just weird that adding +6 mv would cause it to throttle.
Maybe I got unlucky with the silicon lottery or maybe I'm missing something?