Request for Lenovo 3000 N500 4233 Bios Mod

Hello,

First of all the computer data:
Lenovo 3000 N500 4233 with HDMI
Phoenix Version 1.09.
http://download.lenovo.com/ibmdl/pub/pc/...et18ww.exe

This computer has a 9300m gs GPU and its idle temp is 70°C

I discovered why after changing the thermal pads and after an accurate monitoring of the temp.

My CPU is a T9400 and its idle temp is 33 - 35°C. The fan is only controlled with the CPU temp, the PC doesn't take care of GPU temp.
So if the CPU is under 41°C the fan is OFF! Even if GPU is 70°C.

Do I need to modify the bios to decrease the CPU temps in order to switch on the fan at 33°C?

In fact it's my son computer and he is always playing games that use the GPU and it sometimes reach 105°C!!!!!!!!
I have allready underclocked the GPU (max temp is then 95°C but it is still too much), no way to undervolt it!

Thanks

Regards