Quote from majod :

I think nothing can provide better stats than this:
http://store.steampowered.com/hwsurvey

Majority: 2 cores, 5GB+ ram, DX11 GPU.

Nope. A majority is 50 % and more, right?! Regarding the dual-cores you're right, but the 5GB+ option just got 30%, that means about 70% have less than 5GB. So the majority has less than 5GB. And also only 42% have DX11, so about 58% have DX10 and less. 58% being the majority of course.

The numbers I took from the above link, at the time I posted.