What is....."Cas Latency" ?

[paralegal321]

I'm getting ready to do a major upgrade on my computer memory but I'm confused by the words "Cas Latency". I've searched newegg.com and have come up with some tremendous deals on memory but my hold up is defining what "Cas Latency" is. Can anyone define what it is? The ones I've searched say either 2 or 3 Cas Latency.

[JLK03F150]

"Cas Latency" is one of the four primary ram timings. With DDR ram the three choices are 2.0, 2.5, or 3.0 CL. The lower the number, the better the ram performance. However, the real world difference between 2.0 & 3.0 is fairly small. Something in the range of ~5%. You can use CPU-Z to find out the CL of your current ram & just match your new ram to it.