16GB seems low for XP. Should not stutter with your specs though unless system is not well balanced. Here are my specs. They are slightly lower than yours. I do not have issues, XP 11 is running very smooth: i5820k processor overclocked to 4GHZ (stable), 32GB DDR4 RAM, Nvidia GTX970, X99S SLI Plus motherboard, Samsung 950 PRO M.2 x4 SSD (exclusively for XP11).