Backstory: I have a system I built in 2009. Bought a Phenom II X4 Deneb 3.7Ghz and put it in my Asus M2N-SLI a while ago. I read some threads on Overclocking forums and eventually got it to work by upgrading the bios to 5001 beta, only it was stuck at 800Mhz. I eventually got it up to around 2.6Ghz using Nvidia System Tools to increase the multiplier to 13x since the BIOS overclock wasn't working. My power supply went out and while trying to fix it I corrupted my Windows install and had to reinstall. After doing Windows Update and installing all the drivers and Nvidia System tools again, I went to Performance, and Device settings where I did the OC. The setting to change the multiplier isn't there anymore. I searched Google, even called Nvidia tech support and neither were any help, so I turn to you to help me find out why the option is missing for me. Here is a picture showing where it used to be. It was there before the reinstall.
little confused by your question, which is obviously not the ASUS M2N sli motherboard to OC the CPU, and I do not know what kind of Phenom II X4 clocked at 3.7GHz??? and has nothing to do with NVidia (onboard video). should you working default will fine
listed for CPu support http://www.asus.com/Motherboards/M2NSLI/#support_CPU ( which is your CPU ?? )