Hey all,
 
So this is my problem:
 
I have an A8N-SLI Deluxe mobo, with an Athlon 64 3200+. I have three sticks of ram, 2 x 512MB M2U51264DS8HB3G-5T Sticks and 1 x 1GB JM388D643A-5L Stick. On their own, the 2 512MB sticks work, and on its own the 1GB stick works. But in any combination of them (i.e All three in at once, the 1GB and one of the 512MB) the computer doesn't even boot. I tried changing the command rate to 2T and even manually set the sticks to DDR333 in the BIOS (they are DDR400 sticks, all three of them) but none of that works. Please help.

Use either the 2 512,s or just the 1 gig.
 
that is your porblem.

So there is no workaround that will allow me to use both?

Some times yes but sometimes no.
 
i have used both on my a8n sli deluxe.
with no problems.
i have mixed value and extreme.
 
but it is better to have matching ram.

You are supposed to have matching pairs, it says it in the instructions too.

It can't work in dual channel.
It has to revert to single channel and at that point it's better to only use 2x512MB. Just buy another 1GB matching stick. It can't cost more than $35.