To achieve 667mhz CPU speed the motherboard uses a FSB (front side bus) speed of 133mhz with a clock multiplyer of 5x (5x133 is 665 I know) as the FSB is running at 133mhz you have to have memory running at the same speed i.e. RAMBUS as they called it, so things are going to be running a lot faster. 16mb graphics card is really the absolute minimum these days would personally go for 32mb (I have a NVIDIA GeForce based card) however the card is only as good as it's drivers! If you are going to upgrade your pc then go for the best you can afford in your buidget range. Trouble is if you go for the fastest CPU then it is likely that the manufacturer WILL put in lower speck components. A 450mhz intel P3 with a 32mb geforce or G400 would give better frame rates than an AMD 700 with a 8mb crap graphics card, so you have to balance things out. 128mb RAM minimum these days and HDD not less than 10 to 12GB