RAM question

[PurePeon]

PC2100, PC2700 and now PC3200. How do they come up with these? 2100? 2700? 3200? is that the bandwidth it can handle?

 

[BoomAM]

The ratings relate to the theoretical maximum available bandwidth. Measured in mb/s
So;
PC2100, can transfer 2.1gb/s
PC2700, can transfer 2.7gb/s
and so on.

PC2100 runs at 266mhz
PC2700 runs at 333mhz
PC3200 runs at 400mhz.

I have no idea how they work out the actual speeds, whats wrong with 312mhz?
I noticed that FSB speeds and memory speeds are equal to the speeds(in mhz) of intels older processors.
Anyway, someone on the foums will know.

 

[cmdrdredd]

DDR memory runs at 2x the rated FSB. Therefore at 133Mhz with DDR it is 266 and at 166 it's 332(333). It's likely that the memory is running at the 133/166/200Mhz and since it reads both on the up and down (I don't know the technocal word here) it is actually doing double the work so it's effectively 2x that speed.

Course I could be way off

 

[BoomAM]

I think that the term is "both edges of the clock".
Dont quote me though

 

[thorin]

PC1600 = 200Mhz * 8bytes = 1600MB/Sec
PC2100 = 266Mhz * 8Bytes =~ 2128MB/Sec (rounded =~ 2100)
PC2700 = 333Mhz * 8Bytes =~ 2664MB/Sec (rounded =~ 2700)
*PC3000 = 375 * 8Bytes = 3000MB/Sec
PC3200 = 400Mhz * 8Bytes = 3200MB/Sec
*PC3500 = 433 * 8Bytes =~ 3464MB/Sec (rounded =~ 3500)

Now obviously the bus isn't running at 200/266/333/400 it's running at half that and transfering on both edges (rising and falling) of the clock signal.

Thorin