Ak79D-1394 2 memory

I have 2*256M DDR400 Kingston memory running at 266 2-2-2 in bank 1
and 3 of my Ak79D-1394 motherboard. Somebody want to sell me a
Crucial 512M DDR400 that is able to run 266 2-2-2. I know that
noforce1 did have performance drop and issue when using 3 dimm, , is
it the same thing with nforce2. I read somewhere that in nforce 2
there a third memory controller. So there is no issu anymore but does
it affect speed?

Etienne