I'll admit right now that I am overly protective of my Mac Pro, it's my baby. I enjoy using 2 monitors, but I am wondering if these two ACD's are too much, since the one time I tried them both at once performance seemed sluggish. Here's the specs: 2.66Ghz Mac Pro early 2009 Quad-Core 12GB of RAM (3x 4GB) The apple shipped video card is an NVIDIA GeForce GT 120, 512MB of VRAM And I added an ATI Radeon HD 2600 XT for the second monitor; it's 256MB of VRAM. The two monitors are two Apple HD Cinema Displays, a 30" and a 24". Am I being overly cautious, or are these two displays large enough to hinder my system performance if I use them both at once? The 30" is currently using the NVIDIA card and the 24" would run from the ATI. Thanks!