Hey D,
If Abit & your Bios Chip maker come up with a new bios that allows you to use a XP-2800+, yeah it would be ok to use the same DDR as you have now. It is the same as running a XP-1500+ with PC1600 DDR. All the DDR is backwards compatible.
My question is this: Why would you want to get a faster CPU? Is there anything that you think a XP 2800+ would do that much faster in your setup than your Athlon 1.4?
The Truth: Wait until the XP-2800+'s are out, then check the Abit Bios/Download website, or email them with this question, do not trust what some joker who thinks he knows it all(like me), to tell you what you can & cannot run in the future.
Peace Out.............tile
god knows your entire system setup & he would answer your questions if he could just stop laughing