Guys you're going about this all wrong.
It doesn't matter at all how many slots you are using, if you decide either Unbuffered or Registered memory.
All that matters is how many banks each memory stick has.
The Abit KG7 or KG7-RAID supports up to 4 banks of memory if Unbuffered, and up to 8 banks if Registered.
If each of your memory sticks used 1 bank each, then you can use all four Unbuffered. However, if you had a memory chip with 4 banks, then you can only use 1 of those if Unbuffered, or 2 if Registered. Look at the banks on the memory, because believe me, not all memory is equal.