The most instantly noticeable thing about the ASUS P8Z77-I Deluxe has to be the riser card sporting an array of capacitors and providing 8+2 power phase VRMs.  What isn't as noticeable until you use the motherboard is the Intel SRT support, Lucid Virtu and the overclocking options available in the UEFI BIOS.  Being a Mini-ITX board, the singly PCI Express x16 slot and dual memory slots are to be expected but the spacing is such that you should have no problems with full sized DIMMs or oversized GPUs, depending on the cooler and case you choose.  The included dual Wi-Fi antennas are a nice bonus from ASUS as well.  Drop by The Tech Report to see this board in action

"The P8Z77-I Deluxe packs a lot of goodness into a tiny package. We take a closer look at the board's features, performance, and overclocking potential."

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