* MyndPhlyp:

The thread just made me go back and look at my Intel D875PBZ manual.

As long as you are using a matched /*pair*/ of DIMMs equal in speed,
density, and technology in the same slot of both channels you get the
benefit of dual channel. See the following PDF. Page 35 (Figure 9) even
shows a mixed configuration.

ftp://download.intel.com/support/mot...bz_English.pdf

So yes, you can have 1.5GB by using 2x512MB + 2x256MB.

As for whether this is a universal feature among various motherboards, I
suspect not.

It is with all mobos that use dual channel memory and which have at
least two memory banks.

Benjamin