According to the Operator's Manual ( Inspiron 6000 Owner's Manual ), the maximum memory supported is 2 GB. According to the specifications, Dell sold the Inspiron 6000 with Pentium M processors having either 1 MB or 2 MB cache. You would need to research the Intel site to determine what Pentium M processors are available that fit the cache spec. If you look at the spec page in the appendix, you will see that Dell also sold Celeron M processors with this computer. I'm pretty certain that the FSB spec of 533 MHz goes with the Pentium M, while the FSB spec of 400 MHz goes with the Celeron M.