Hi there, I was hoping someone could help me. I have just purchased a second hand Mac Pro as a work machine, and I am looking at giving it a bit more grunt. I mainly do video/graphic work using After Effects, Premiere and Photoshop CS5. The machine I have purchased is a Mac Pro 2009 2.66GHz Quad core Nehalem with 3GB Ram. I obviously want to upgrade the RAM but I have a question I was hoping someone could help me with. I have read that if the first three RAM slots are used with matching RAM cards, eg. 3x4GB then the machine will run in triple channel mode. Is it then the case that if I fill all four slots eg. 4x4GB the machine will only run in double channel mode and be slower? In which case would it be better to run three slots and less RAM fast, or four slots and more RAM slow? Or have I got it all wrong and the case is that three of the slots will run in triple channel mode and one in double channel mode? In which case it would be fine to fill all four. Working with video and doing motion graphics obviously the more RAM the better, but I don't want to make the system run slow. Ideally I am thinking about 4x8GB does anyone have any experience of this? I am looking at this from an After Effects/Premiere point of view, but also from overall point of view as well. Sorry for the long post.