Unless this is something brand spanking new, it`s previously been that in order to have dual access to 2 mem strips, they would need to be the same size.
Emphasis being, if u had a 256m and 512m strip in paired slots, trying to access something at about the 384m point on both isn`t going to happen.
Gotta be something new`n`clever
Wonder if all X38 chipsets do that. Nice find