The Maximus V Extreme is Asus' flagship Z77 motherboard, and that's reflected by its £310 price tag. That's actually about £45 more than you can spend on the most high-end Ivy Bridge CPU. Fortunately you do get something for your money.
Asus has added pretty much any feature that could be even remotely useful for overclockers, who are the intended audience for this board. The somewhat more affordable Maximus V Formula board is aimed at gamers. The SupremeFX sound card and optional ThunderFX module on that Formula board are not present on the Extreme. Instead, the Extreme has lots of other features you won't find on the Formula, or most other Z77 boards for that matter.
The motherboard is of course constructed around a Socket 1155 processor socket and is suitable for both Sandy and Ivy Bridge processors. The board has five PCI-Express x16 slots, with slots two and three sharing the same function. Asus clearly thought about that one, because it lets you combine four two-slot graphics cards, or three three-slot graphics cards.
A PLX chip makes sure that each video card hass access to enough PCI-Express lanes. This is necessary because normally a combination of three of four graphics cards is not possible on a Z77 board with its 16 PCI-Express lanes. The PLX chip more than doubles that amount, when you use four video cards you even get up to 40 lanes (16/8/8/8) even if the actual link to the CPU remains limited to 16 lanes. Asus has also been nice enough to include three- and four-way SLI bridges. The board also includes an open PCI-Express x4 slot.
There are eight SATA connectors on the board, six SATA600 and two SATA300. The ninth internal SATA connector is intended for conversion to eSATA via a bracket. There are eight USB 3.0 ports, four of which are external, and there are 12 USB 2.0 ports. The board has a Gigabit LAN connection from an Intel 82579V chip. You can read the rest of ASUS Maximus V Extreme preview on Hardware.info.