1. CAS2 is much better than CAS3 by a factor of 30% raw performance or about 15-20% using a chipset. Anybody who says otherwise needs to at least graduate highschool first, get a BS in EE, Physics, & Math then come talk to me.
2. CAS2 memory is NOT!!!! hard to find.
www.muskin.com and
www.crucial.com I list off the top of my head without using a dictionary to spell it. And it is affordable. I lived in the days where memory when memory was $200/meg.
3. CAS3 to CAS2 memory will improve ALL systems that are secondary memory based which is pretty much everything that doesn't reside in locked level 1 or level 2 cache...well is pretty much almost everything you install
4. You don't have to buy the best CAS2 memory...but good CAS2 or even CAS3 is a must if you want your system to run well all the time or are even "THINKING" of overclocking.
Have a good day...I'm going to bed....
-Navi