The ASRock Z77 Extreme6 is a motherboard targeted to users who want a product one step above mainstream solutions. While it provides the same basic functionalities of the Z77 Extreme4, it comes with one additional PCI Express x16 slot (which is 2.0 and works at x4 speed, though), allowing you to install up to three video cards in SLI or CrossFireX configuration. Another highlight of this product is the presence of a mini PCI Express slot, allowing you to install an SSD or a wireless network card using this form factor.
Under the hood, however, is where lies one of the most important aspects of this motherboard: the PLX PEX8605 switch chip. Since the chipset doesn’t have enough PCI Express lanes available to connect all the devices that are present on this motherboard, this chip automatically switches PCI Express lanes in order to provide the highest performance possible to the device that is requiring performance at any given moment. On motherboards without this chip, you need to manually disable devices (namely, USB 3.0 and SATA-600 ports) that you are not using if you want to achieve the highest possible performance on the ports that are being used.
Also noteworthy is the high-end audio codec used by ASRock on most of its motherboards based on the Intel Z77 chipset, the Realtek ALC898, which provides very high signal-to-noise ratios (110 dB for the outputs and 104 dB for the inputs), allowing you to use the on-board audio from this motherboard for professional tasks, such as audio editing.
If you are a user looking for “something more” but don’t want to buy the most high-end (and most expensive) motherboard around, the Z77 Extreme6 is a good candidate for you. Otherwise, you can pick a more mainstream product, such as the Z77 Extreme4 from the same manufacturer.