VCore lowering drastically (momentarily) on high CPU load

[Zipppy]

I've been having an issue ever since I got my new PSU, the new EnerMax one I've been talking about a bit, and it's that the VCore drops approximately 0.10V on high load (happens on graphically intensive games especially). It holds the voltages for everything else much better than my previous PSU, some cheap generic one I had to work with, until I had enough money to buy a proper one.

While this drop happens, my CPU underclocks to 800 MHz from the normal 3100 MHz for a couple seconds then goes back up to regular speed (read by CPU-Z), I've also tried forcing the voltage to 1.30 through the BIOS, no difference, it still does the dropping and it underclocks the same amount. The temperatures of when it's on load is about 50 degrees Celsius, on idle, it's around 40, maybe even less if it underclocked on idle.

My specs are below

ASUS M2N68-AM Plus MicroATX motherboard
ASUS EN GTX560 graphics card
EnerMax EMG700AWT PSU
AMD Athlon II X3 445 Rana (running stock at 3100 MHz, with 15.5 Multiplier forced via bios, seems to drop the multiplier on load)
Windows 7 64-Bit

I would like some insight on this issue, since every other power output doesn't drop when this occurs.