Over the years the speed of your system memory has been slow to catch up with the clock speed of your CPU. The fastest CPU speeds currently are up to 2.53GHZ, this number is increasing radpidly every year. On the other hand RAM speeds are only at 333MHZ (166x2 DDR) or 800MHZ (400x2 RDRAM) and the speeds of memory is not growing as fast as the speeds of CPU's. One can remember back when the difference of RAM speeds and CPU speeds were not as great. For instance, back in the day you were blazing along with your brand new PII 266MHZ CPU and 66MHZ SDRAM. This amounted to only about a 4x difference but now, 5 years later, the difference is about 8x.