Originally Posted by 100PARIK
Want it stable, cheap, fast, and nice? ...get Mushkin Redline with CAS 6
Lower CAS isn't going to help on an Nehalem build, the IMC natively reduces latency so memory frequency > tighter timings.
HOWEVER, a good 1600MHz kit with low timings will OC quite well just by loosening the timings a bit, and giving a slight bump in volts.
You're not going to see a huge jump in real world performance based between 1600MHz and 2000MHz unless you're doing pretty specific things (gaming, basic use etc won't matter).
Of course with the 2000MHz kit you'll be be able to just underclock it if need be to compensate for pushing the BLCK very high if you're doing some crazy OCing.
Honestly the pros and cons are pretty equal no matter what way you cut it up; I'd just go for whatever gave you the best deal between the two