Hello rookie here having a blast OCing my old hardware. Currently benchmarking my old ASUS 650TI (1gb, 980 MHz GPU Clock, 1350 MHz Memory Stock)

I have my 650TI at 1.137V which is the maximum I can get it to via MSI Afterburner. 
Right now using stock cooling I can get the GPU Clock to 1220 MHz with a Memory Clock of 1450 MHz and I'm basically on the edge of stability. The maximum temps I see are around 60C, even with the stock air cooling I'm convinced I can squeeze a bit more performance out of it.

Is there any way to exceed the 100mV limit, or in order to do this would I have to do something outside of programs like Afterburner? 

Appreciate any input - thank you,
  Feltyham 

Have you tried the very old versions of msi afterburner or nvidia inspector to see if you can add a bit more voltage ? If that does not work you will have to find the datasheet for the voltage controller and do a hard volt mod.

It's a Kepler GPU, so you might have some luck modding the BIOS. There's a tool especially for changing the voltage in the BIOS (though I never succeeded in it working properly).

Excellent thanks for the advice gentlemen, currently benching 775 CPUs but I'm sure I'll get back to trying to push the 650TI a bit further.

Cheers! 

Nice, I also have a 650ti on my S775 bench right now. Not sure if I want to push it beyond that 100mv mark, the VRM's are already pretty hot by themselves.