is there a difference between ddr and ddr2?

[kanezfan]

I just bought an Epox 9NDA3+. I'm running my old ass 2x256 pc2100 and 1x512 pc2100, mismatched brands. I know, I know, how could I do such a thing!!?!?! Problem is the system only sees 768mb of ram and not the whole 1gig. I know the ram is fine, but I'm like why not get new ram since I just went from an athlon 2400+ to an A64 3000+. So I go online and see DDR and DDR2 for sale. Does DDR2 work in any mobo that runs on DDR? Is it just faster than plain old DDR?

Thanks

[BillLeeLee]

No, DDR2 and DDR1 aren't compatible with one another. DDR2 is 240 pin, DDR1 is 184 pin.

DDR2 can be faster than DDR1, but this doesn't have to be the case. You could have PC3200 DDR2 RAM as well. However, the way DDR2 is is different from DDR1. DDR1 can take two bits per cycle, while DDR2 can take 4 bits per cycle.

So PC3200 (400 Mhz) RAM in DDR1 format is actually 200 Mhz x 2, while in DDR2 it's 100 Mhz x 4.

Athlon 64 motherboards won't support DDR2 until the M2 socket later this year (a couple months I think).

[kanezfan]

So all the DDR2 is being used only on Intel systems huh? Didn't know that. Didin't know it was 240 pins either. Glad I asked, I love learning new stuff.

[(cf)Eclipse]

not to be annoying, but your question is answered in the memory purchasing sticky :p