I'd go for it... Even if it doesn't fix your Vista problem you'll have a much more adequate amount of memory for playing the next gen games.
Asus Sabertooth 990FX | AMD Phenom II X6 1090T | 16gb G.Skill Ripjaws X DDR3 | Thermalright Silver Arrow
2 x Sapphire HD 6870 1gb CrossfireX | LG 10X Blu-Ray Rewriter | PCP&C Silencer 750 Quad | Fractal Design R3 Case
60Gb Patriot Pyro SATA III SSD | 1Tb WD Black | 3 x 2Tb WD Green | 2 x 360Gb Seagate Barracuda