ram chip numbers - what do they mean?

[coinheaven]

can anyone tell me what the model #'s mean on the ram chips on nes boards? some end in 10L, 12L, 15LL etc. i had heard they were the speed, but would like some info from you guys. thanks!

[blargg]

10 = 100 nsec access time
12 = 120 nsec
etc.
if the value is large and it's a chip made in the last decade, the time is in nsec, so for example a 55 is 55 nsec, not 550 nsec.

L and LL refer to the current needed for low-power retention mode. L is lower power than normal, LL is even lower than that.