Just wondering if you can mix the size of RAM modules in a D10. I'm considering purchasing one and it comes with 2 x 1Gb installed, I was wondering whether I could add another 3 or 4 2Gb modules in? Also, do they have to be matched pairs i.e. would I have to add 4 rather than 3?
any system board that uses fully-buffered DIMMs (FB-DIMMs) requires modules to be installed in matched pairs. however, you don't have to match sizes across the entire population. on top of the 2x 1GB modules installed from the factory on your D10, you could install 2x 2GB or 4x 2GB modules as you're planning but not 3x 2GB as that wouldn't work. you could even have 6x 4GB + 2x 512MB for 25GB total if desired.
modules don't have to match brands across the population but it's usually best to match brands across each matched pair whenever possible. sometimes a mismatched brand across a matched pair will be rejected (ie; 1x 512MB OEM micron module plus 1x 512MB kingston module). clock speed and latency timings usually have to match for the pair to work so pay attention to this on the stickers.