how does cycle time affect performance>

[T400plus]

I got 2+2(4GB) for my old T400.I got kingston CL7(whatever ir means).I was gloatting over the good memory till a wise guy told mei should have actualy got CL5.A lot of the memory here (higher Mhz like 1333,..) are CL9.
I am inquisitive. what does this CL5,CL7,Cl9 stand for and how relevant are they?.
my tiny super heavy notebook is a 9 battery T400 with a p8400.

[yak]

http://en.wikipedia.org/wiki/CAS_latency

[T400plus]

thanks.I read it.
Now,
does it mean that there is nothing like CL5 for pc-8500 for T400(1066).
this 1066 is T/s and not bus frequency ? which looks like it is a misearble 533 only.

[donzoomik]

The simple answer is that even if you're doing something extremely RAM-intensive, CAS latency has next to no difference.
1066 is marketing, actual clock rate is 533, but that's the deal with Double Data Rate (DDR) Again it has no difference, since you can't get DDR3 with 553 as marketing.