What NS is this RAM ?

[DDR-PIII]

Its off my video card, gf6600256mb.

hynix - hy5du561622ct-4

also how many mhz is 1ns,2ns,3ns,4ns etc.. ?

[Tebore]

Should be 4 ns.

Hyndai doesn't always stick to a standard convention. For instance DT-43 meant 400mhz at CAS 3. DT-5 meant 5ns.