System requirements.

I was wondering whats the most accurate way to read system requirements since they are based on desktop parts and mobile Gpu's are not equal in strength.
Say the recommended GPU is a Nvidia 460 (such as Battlefield 3) and you have a 460m. How would that compare.

 

They are nearly the same but the GTX 460 has 336 Shader Units
while the GTX 460M has only 192 Shader Units, so its not equal.

Or like the HD 5870 has 320 Shader Units and the HD 5870M has only 160..

The gpu companys only use the same name and put a "M" behind it but its still not the same power as the desktop ones...

For example on Crysis, max details the GTX 460m reached 34,1 FPS on 1600*900 without AA, while the desktop GTX 460 reaches 48,7 FPS

 

Basically, you compare the amout of shaders first, then the clock speeds. The 460m GTX has 192 cuda cores the same as a GTS 450. The 6970m has 960 shaders, the same as a 6850, my one has 1120 shaders, same as a 6870. Usually the mobile GPUs have similar specs to the GPU one model down from their equivalent.

 

Is there a site like notebookcheck that lists the performances and benchmarks of all desktop gpu's so theres a chance to compare?

 

well if you look closely at notebookcheck comparison charts, they list desktop cards as well, they're in black and not a link unlike the mobile chips which are red and are a hyperlink.