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DDR: 266, 333, 400.. big difference?

Posted: Wed Jul 07, 2004 8:19 pm
by intx
I've noticed there are various different speeds in ddr memory. But how much of a performance difference would I notice between them? Do I really need 400mhz memory, or would I only notice a minimal increase like with dual channel memory?

Thanks

Posted: Thu Jul 08, 2004 3:39 am
by Spod
Athlon XPs aren't that sensitive to bus speed, but you want to get RAM that matches the FSB you intend to run your processor. If it's a 400 MHz FSB Athlon XP, you need DDR400 memory to match it.

You can run your RAM at a different speed to your FSB, but the latency penalties are relatively significant. If you get a 333 MHz FSB Athlon XP, it's better to run your RAM at 333 MHz (a 1:1 ratio) than to run your RAM at 400 MHz.

Posted: Thu Jul 08, 2004 8:54 am
by Skylined
Only get a higher rated DDR if you're going to overclock.
But as Spod said, always try to match your CPU's FSB.

For example I have a 1700+ that's stock 133MHz FSB, but I'm overclocking it with a FSB of 166MHz, so I bought DDR333 to match that FSB. ;)