I have an Inspiron 6000 that uses a Pentium M 715 (1.5 GHz/400MHz FSB). I was planning to upgrade the ram. I was wondering if it was better to get DDR2 PC3200 or PC4200 sodimms? I believe that since the FSB is 400MHz, the PC4200 would clock down to PC3200 speeds. But I am not 100% certain about this. Also I noticed that most PC3200 is CAS 3 while PC4200 is CAS 4. I am not sure how CAS effects the ram.