I currently have 2 GTX 590's in SLI. I was hoping someone could help me on how to raise the max VCore so I can successfully overclock these cards. It seems in programs like MSI, EVGA tuner, and others, that they max out the VCore at 925. I know these cards have had problems while overclocking. I do not want to do anything crazy, just have the opportunity to eek out a little more from these cards. I know it is possible as I've seen examples of people doing it on youtube, and in forums and such. Could someone help me with this? I would really appreciate it. Thanks in advance.

Intel i7-2600K
2 EVGA GTX 590's Classified
ASUS Maximus IV Extreme Z
16GB Kingston HyperX RAM
2 240GB Patriot Pyro SSD's, 1 2TB WD Caviar Black 10,000 RPM HDD
Antec 1200W PSU
CoolerMaster HAF X Case
EK waterblocks for CPU and gpu's, 2 separate loops