Got my new Mac Pro 2.8 octo with standard 2GB memory last week and its brilliant. Really pleased. Just put in 4 x 2GB memory from OWC (slots 1,2 top card and slots 1,2 bottom card) and it is now slower when I use my 3D app Strata CX 5.5. Strata is a 32 bit app so it has a 4GB limit, but when doing a test render activity monitor shows only 350-400MB real memory being used and a whopping 1.4 GB virtual memory being used. Does anybody have any ideas as to why the real memory isn't being used instead of the slower virtual memory. Is it the app or the OS that controls this? I wasn't expecting massive gains in render speed, (it's quick enough as it is), but its an expensive way to slow your machine down. I have been advised that the more memory you put in the larger the OS overhead, is this the case? I am hoping the 10.5.2 update might help but I'm not hopeful. Is anyone else finding their machines slowing down?