The first thing we noticed about Gigabyte EP45C-DS3R is the presence of two PCI Express x16 2.0 slots. These slots are compatible with ATI CrossFireX. If you have two video cards with NVIDIA chips, you can use them in independent video outputs, but not in SLI mode, not supported by Intel P45 chipset. Note, however, that only one PCI Express X16 slot (the blue one) works at x16 speed, while the other one (orange) is actually a PCI Express x8 slot. The board also has three PCI Express x1 slots and two standard PCI slots. There is no extra power connector for slots.
We can also see in Figure 3 the serial and parallel port connectors. These ports do not exist on the rear panel (see Figure 6), but you can buy connectors in order to use them.