Single Channel Mode
2x512MB DDR 400MHz CL3.0
1x256MB DDR 400MHz CL3.0
Channel A, DIMM 0 512MB
Channel A, DIMM 1 256MB
Channel B, DIMM 0 512MB

659 3DMarks
SM2.0 Score: 249
HDR/SM3.0 Score: 219
CPU Score: 950

Dual Channel Mode
2x512MB DDR 400MHz CL3.0
Channel A, DIMM 0 512MB
Channel B, DIMM 0 512MB

669 3DMarks
SM2.0 Score: 252
HDR/SM3.0 Score: 222
CPU Score: 951

Not much of a difference but there is something...

I always say that it's not a big enough deal to spend more for dual channel if you can get the same amount in one stick for cheaper.

that's it =\ !!? ... hmmm... thought there will be bigger difference =\ ...

What's the effect on overall bandwidth and latency? What about multitasking?

Judging by those scores being below 1000 I'd have to say that that pc is a bit on the old side to the point where the extra bandwidth could never be utilized by it anyway. What would the difference be on a system that is much more capable and higher scoring?

I would be interested in seeing this test done on a more current rig as well.

How about a test that's designed for testing memory like Sisoft Sandra rather than a 3d Graphics test?

Dual-channel isn't going to help 3d rendering in any significant amount. It does help where memory is required, but not the "double" performance many think.

http://www.tomshardware.com/2007/10/17/par...ing/page12.html

What chipset did you use? some enable dual channel even with different amounts of ram on 2 channels.

Haha +1