I've been using a Dell studio XPS 1645 (i7 720qm,ati mobility radeon 4670[r730], intel pm55, samsung 830 128GB ssd) system under windows and linux depending on my programming platform and software(ide,ise,etc...).
I've always had a huge power draw, therefore more heat coming from the system and the louder the fan got, under linux unlike windows.
The difference is huge, my battery lasts 50% more under windows than linux.
I am using windows 7 64-bit professional(retail) and i am using debian 7 (testing) with kde 4.8.x and obviously the oss gpu driver and the classic other firmware and drivers that are available for the rest system.
no matter what I do on linux, browsing or coding or watching videos with flash or with html5 you can really fry potatoes with it. If I switch to tty0 for example and shutdown kdm or gdm3 when i have xfce4/gnome , the laptop gets cooler and cooler and the fan at last stfu.
This fact can point directly to the gpu and the driver, but what else can cause this?
I've been searching the driver's site and cannot find any way to set custom clocks to the gpu, if this is going to solve the problem(i don't think so, the gpu is still going to struggle again but with lower clocks now).
I see others get the double time under linux rather than windows and this happens only to me.