Trying to understand DDR ram...
 

Memory: Supports DDR 200/266/333 via 2 184-DIMM slots for up to 2 GB.

This is for the ICE Cube bare bones mini PC on thinkgeek.com


Is the 200/266/333 the bus speed? or what?


I always see PC 3200, 2700, etc when I look for DDR ram..

Here's a pretty good explanation:

http://www.white-chocolate.com.au/Ma...rexplained.htm

Hope that helps.

Yes, the 200/266/333 is the front side bus speed of the RAM. The faster the better, of course. PC2100 is 266 MHz FSB, PC2700 is 333 MHz FSB, and PC3200 is 400 MHz FSB. The ram names (2100, 2700, etc.) are simply there to recognize which type of RAM it is, much like AMD Athlon XP processors. An Athlon XP 1900+ doesn't run at 1900 MHz, it runs at 1600 MHz or 1.6 GHz. Just like the Athlon XP 2500+, which runs at 1.8 GHz, not 2500 MHz.

-Lasereth

It's even worse: 200/266/333/400 is *not* the FSB (front-side-bus), but is 2 * FSB, because it's "double-data-rate" memory. DDR200 runs at 100 Mhz, DDR266 at 133, 333 at 166 and 400 at 200.

That's similar to the supposed 800 Mhz FSB of the new Intel P4's with Hyperthreading: that's actually 4 * 200 Mhz FSB...

The PC2100/PC2700/PC3200 shows you the maximum "speed" of the memory in MB/s. DDR400 (2*200 Mhz) has a (theoretical) throughput-speed of 3200 MB/s.

And to further confuse you: those new HT P4's (and Athlon Nforce2 motherboards) support "Dual-channel memory", which lets two DDR400 chips work together to act as a single chip with a throughput speed of (theoretically) 2*3200 = 6400 MB/s...

Yeah, I decided to not go into that and try to simplify it. But to add to the confusion, Athlon XP processors also have double FSB speeds. That's why you see 133 and 166 in BIOS instead of 266 and 333!

-Lasereth

Thanks guys. Told me what I need.ed

thanks, me too. i learned a lot.