ASRock H55DE3 comes with two PCI Express x16 2.0 slot – the first one always working at x16 and the second one working at x4 –, two PCI Express x1 slots and two standard PCI slots. The x16 PCI Express slots support CrossFire configuration, but not SLI.

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Figure 2: Slots.

In Figure 2, you can see how H55DE3 has a serial port (header labeled “COM1”), but the motherboard doesn’t come with the adapter to use this port.