Memory timmings

I am bettween this 4 memories ddr2 technology.
a) ddr2 400 cas3
b) ddr2 533 cas4
c) ddr2 667 cas5
d) ddr2 800 cas5

so givien in mind we are not interesting in frequense.
nor in the theoretical maximum bandwidth
which one will deliver data faster?
First word Fourth word Eighth word
ddr2 800 cas5 12.5 ns 16.25 ns 21.25 ns
ddr2 667 cas5 15 ns 19.5 ns 25.5 ns

this is taken out from wikipedia
http://en.wikipedia.org/wiki/CAS_latency
the link but sadly it does not say anything about ddr2 400 or 533

so ddr2 400 with cas3 will have lower latency than ddr2 800 cas5?

(in case of wondering in what case scenario i am not interesting in bandwidth i want to install the memory to acard ans-9010 so since it will limit the bandwith to 200mb/sec there lays witch is better in latency and access times)

 

more info about the modules
ddr2 400 ddr2 800
tCK 5ns(min)-8ns(max) 2.5ns(min)-8ns(max)
tRC 55ns(min) 60ns(min)
tRFC 105ns 127.5ns
tRAS 40ns(min)-70,000ns(max) 38ns(min)-70,000ns(max)

so we see a lower minumim at tCK for 2.5ns but the same max
is it safe to take the average of min and max value and thus have
for ddr2 400 6.5ns and for ddr2 800 5.25ns which will give ddr2 an advandace of more or less 1 ns?? at this area?
at tRC since it does not say max values it favors ddr2 400
at tRFC it clear ddr2 400 has an advantage of 22.5 ns
at tRAS both operate the same with a maybe little favor at ddr2 800.

(by the way what is tCK, tRC, tRFC, and tRAS??)
what they measure so someone can draw any conclusion from this numbers thanks

 

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

http://www.techpowerup.com/printarticle.php?id=131

 

So given the techpowerup article the ddr2 400 memory will suit me best in my situation. If i am not that mistaken.
Thanks for the links.