Speaking of PCI Express, are the speeds of each slot the same as with the Power Mac?
In the Power Mac, each PCI Express slot had a set bandwidth, expressed in terms of lanes—the graphics slots was the fastest at 16x, with one 8x slot and two 4x slots as well. With the Mac Pro, Apple says that when you boot the computer after installing a new PCI Express card, the OS will let you choose the amount of bandwidth to dedicate to that slot. Apple told us that the total amount of bandwidth available to the PCI Express bus is less on the Mac Pro than on the Power Mac, but said the ability to direct that bandwidth as needed should make up for such a shortcoming. They also told us that there’s more power (total wattage) available to the PCI Express bus, letting you power two Nvidia Quadro FX 4500 graphics cards.
