So I have 3 1G 400 sticks in 3 of my 4 dual channel slots. It is comming up as 333 single channel. Should I switch to 1 1G and 1 512 stick in each channel or 4G all together? I have XP so I have heard going to 4G wont give me a benifit. Also any ideas on why the 400 memory is comming up as 333? I removed the new 1G 400 and it is reading 400 now. I think I am going to return it to Newegg for 2 512 400s.