I am looking to build a gaming PC sometime in the near future and I am unsure about whether to go for 2GB of quicker RAM (e.g. 800+MHz) or 4GB of slower RAM (533MHz). I appreciate there are other factors to the equation but I am asking purely as a rough guide to getting the most from my memory in the future. I would like to build a machine that wont need too much upgrading to run next year's games like Crysis etc. Any help would be much appreciated.