Last night I bought a Mac Pro from someone on Craig's List - a Late 2008 2.8GHz Dual Quad-Core. He upgraded is GPU to an ATI Radeon HD 5770, but he installed it in SLOT 3 instead of SLOT 1. I asked him about it and he said, "Well, it IS the 16x PCIe lane." Is he correct or should that go into SLOT 1? I always thought the GPU was supposed to go into SLOT 1.