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.
You're losing a bit of speed by not running it in dual channel. I recommend going to 4 gigs regardless though. Although Windows can't address it all, your system will benefit from it. Plus the fact that you can always migrate it to a newer system.
It's better to have an equal amount of memory in each channel. Some Intel boards allow for 3 slots in dual channel.
On some computers supporting DDR333/400 memory, if the memory timing does not match (like having CL2 versus CL3), it will default all memory to DDR333 even if all memory supports DDR400. The best bet is to take a look at your current RAM and get a part number, which you google to find the timings. Newegg should list the timings for all the ram it stocks on its website. Find something that matches your stuff.