I do alot of extensive work with my Quad 2.5 G5, HD video editing and canon 5DII Raw files which are 24MB in size each. I find my computer to slow down when working with each. especially raw files in aperture. so i dont myself maybe upgrading the ram will help, I currently have 5g Ram. HOWEVER when i check the ram when my computer slow do i see that there is some free ram not in use like 2g. So my question, do i upgrade to a newer mac pro or do I just need to upgrade the ram because it doesnt have do with the free Ram reads I am getting? also one thing I also noticed is when i copy files from one place to another my computer lags horribly, the HD playback keep lagging and dropping frames. what you thing is causing that?