Hmmm, i think that you're supposed to disable a few safety
checks and up the voltages. I'm not an expert and since it's a
lappy, it's a bit more tricky.
In there some where there's(that i know of) a CPU, Motherboard and
internal heat sensors, fail safe to prevent ur comp from melting in
case of overheating.
IF im not wrong, step 1 involves disabling those fail safe, THEN
you up the voltage. But if its a lappy (Chances are base on the
model, it's a poly lappy.), it already have a heat issues. I think
you also can save BIOS setting too, since i dont think you can flip
the CMOS jumper if you did something wrong.
There's a limit OEM heatsink/fans can do though, look out for the
"usual suspects"(I.E blue screen of death. 
).
Why u wanna overclock ur gpu, lappy some more? Playing GRAW2?
