There are many conflicting results regarding memory compatability with the Abit KR7-series boards. Some have good results with 2700-rated memory and some don't.
Visit Paul's FAQ at viahardware.com.
I also suggest you visit the 'Abit Motherboards' forum at amdmb.com. That forum is very active and discussion is specific to Abit board user posts. All the good stuff - and all the bad stuff.
I have Abit KR7A/R with one stick of 256 Corsair XMS2400 that is just great.
Hope this helps!