I'm an IT Manager and we're about to upgrade a bunch of Dell D820 laptops from 2gb to 4gb(or 3.25gb due to the infamous 32-bit memory limitation problem) for the many vmware machines we run. Memory prices on large memory sitcks seems to have plummeted lately.
As of right now, we have the choice of getting PC2-4200, CL4 2gb dimms, or PC2-5300, CL5 2gb dimms. As it is, most of out laptops already have 1x 2gb PC2-4200 CL4 dimms in them. So my question is, does that increase in CAS latency lower performance to make the clock speed increase negligible? My limited understanding of CAS latency tells me that even though memory timings is a complicated subject, a lower CL is generally better. Also, for dual ranked DIMMs, would it be a problem mixing these clock speed ratings and brands? We want to be sure to get the dual rank performance boost but I wonder just how identical the two chips need to be to ensure this happens.
Thanks for your help.