Unforgiven hit the nail on the head. Be happy with what you have. With that MB I doubt the use of pc2100 ram will help(it only has a 266FSB for memory). As to your friend, what MB and speed of ram does he have? Also what is his video card?

Your system is on the lower rung of qualification for Doom3, but my rigs are not top notch either. Be happy with what you have.