YOu seriously need to read.
YOu can load the memory banks and the COmmand Rate will merely be reduced to 2T (as with any board except some lucky 955X boards).
No offense but you have no idea what you are talking about:
The 939 dual channel only supports 1 single dimm or matched pairs.
Ummm no. You can use 1,2,3 or, 4 dimms. Matched pairs mean absolutely nothing. Additionally, with 4 dimms the older cores (pre-venice) use a 2T command rate and underclock to 333mhz.
You could try 2*512mb + 2*256mb to get 1.5gb, but there are no guaruntees that this will work. The A64 controller is super picky, and you would probably wind up running with reduced bandwidth + 2T + poor timings (if at all).
Why wouldn't this work?? It is not super picky. It works the same way any other board works. As for reduced bandwidth, i have no idea what you are talking about; the same goes for not working at all.
-Kevin