I've setup 5x boxing on an Alienware M9750 (core2 duo T7200, 4GB ram dual go 8700GT 512 running SLI & Vista Ultimate 32bit)

the main was running at 60fps (low detail settings and the 4 slaves were running around 25-30). quite surprised as i didn't think it would be quite so playable.

price of the laptop was £2,200 ($3,843 approx)