I am building a server for use as a web server (PHP,MySQL), it will also be using this same build for another system that will run as firewall and web cache running Untangle Server. I am using a core i5 quad, and H77 chipset mini itx for both builds. For this use would I be better to buy memory based on CAS or Bus Speed?
This may help: http://www.anandtech.com/show/6372/memory-performance-1... Honestly you'd need high Internet bandwidth to measure a minimal performance difference. DDR3-1600 CAS9 or CAS10 is fine for such an application. To improve performance, buy a slightly faster processor instead of more expensive memory modules.