What is PC2100, PC1600....

[EdEd]

Hi guys,
I have been looking at DDR Ram and I found the PC2100, PC1600 and some others. Are those Mhz like PC133?? If I want to use TB running 266 fsb, which one should I use? How about if 200 fsb?? Thank you for any inputs!!

EdEd

 

[Mookow]

PC1600 is DDR RAM running on a 100MHz FSB. PC2100 is DDR on a 266MHz bus. The numbers (1600 and 2100) refer to how much theroretical bandwidth they provide, in MB/sec

 

[Mookow]

Oh, just to clarify, get PC2100 if you want to run a 266 FSB, and PC1600 for a 200 MHz FSB.

 

[Noriaki]

Yeah...what mookow said. DDR needed bigger PC numbers than Rambus so they changed what it means...
With SDRAM PCxxx is clockspeed, with Rambus it's clockspeed adjusted for DDR, with DDR SDRAM it's peak bandwidth. Bleh :| Marketting.

100Mhz * 2 * 64bit = ~1600MB/s (200Mhz DDR Front Side Bus)
133Mhz * 2 * 64bit = ~2100MB/s (266Mhz DDR Front Side Bus)
150Mhz * 2 * 64bit = ~2400MB/s (300Mhz DDR FSB)
166Mhz * 2 * 64bit = ~2700MB/s (333Mhz DDR FSB)

etc etc.

The MB/s number gives you your PCxxxx rating...it's really dumb.

If you want a quick rule to figure out what PCxxx = what FSB do this:
Divide the PCxxxx number by 8, and you get roughly what FSB it wokrs out to. 2100/8 = 262...
Now the PCxxxx things are rounded figures...266 actually gives 2128MB/s of bandwidth...but if you divide by 8 it gives you roughly what the number is (it's exact in some cases, like 1600/8 = exactly 200).

 

[RSI]

Good info here guys.

Man .. imagine having 384MB+ of this insanely fast ram! I'm used to using slow-ass EDO and slightly faster PC66 SDRAM. Now I've moved up to PC133.. well it's running at 100, but it's CAS2 "turbo" PC100 and it's 256MB, so it seems pretty fast in comparison to anything I've used before. Plus I get pretty high memory scores in benchmarks.. hehe.

 

[EdEd]

oic, thank you for your answer Mookow, nice and clear.

DDR needed bigger PC numbers than Rambus so they changed what it means...
This is a nice one Noriaki.

EdEd

 

[RSI]

Holy crap! I just checked your sys in your profile... That's insane man, 512MB of super-ram!

 

[EdEd]

How did u see that?? I don't know we can do that
I do Photoshop and graphic design sometimes, so a bit more ram. (SDRAM are dirt cheap now)