Memory question for an Abit IS7 board

I am upgrading my mobo and cpu from a Athlon XP 1700+ and ECS K7S5A Pro to Pentium 4 2.8c 800mhz fsb and the Abit IS7 board.

Because of budget issues, I need to keep my current memory, Crucial pc 2100 512mb(1024mb total on 2 sticks) in the new board. I will be upgrading to better memory when I can.

I have seen some reviews that say ddr 400/333 only and some reviews that say ddr 400/333/266. Will the pc2100 memory work in the Abit board?

Yes, it will work.

Like Crotale says, it'll work... at least running default speed if you use the 400 n/b strap and the 3:2 memory ratio. But at 200 FSB (default for the 2.8C) then that's running DDR266. Whether you can overclock depends on how well your RAM does, but dual channel Intel systems make it tougher to O/C RAM. But, it'll tide you over until you can scrape up the cash for better RAM.