In our recent group test of 37 Haswell motherboards MSI's most high-end motherboard wasn't included. We've since had the opportunity to test the MSI Z87 XPower, a motherboard that's aimed at the most avid overclockers out there. We compared it to other motherboards we tested.
The XPower is positioned above the MPower and MPower Max motherboards from MSI, and its lineage is obvious with the yellow color scheme indicating it's meant for serious overclockers. We'd argue that for motherboards in this price segment looks do indeed matter, and MSI definitely succeeded in that department with the design and black/yellow color scheme. The MPower and MPower Max boards are also made for overclockers, but the XPower really begs to be used with phase-change or LN2. The board is supposed to be able to supply up to 1920 watts of power to the CPU. That's in theory, because MSI's own tests show that a Core i7 4770K Haswell CPU at 3.5, 4.4, 5.0 and 6.0 GHz draws 100, 150, 250 and 500 watts, respectively.
Differences with the MPower Max
When you compare the MPower Max to the XPower (click here for a comparison table) there are a number of differences. The XPower has more PCI-Express x16 slots, five instead of three. Four of them are connected to a PLX PEX8647 'lane duplicator' chip, which makes it possible to have two graphics card with 16 lanes each or four GPUs with eight lanes each. Unlike the other board, the XPower supports 4-way SLI. The fifth slot (physically the second) is connected directly to the CPU, circumventing the PLX chip. That's to prevent the very minor latency, which overclockers will appreciate. It could get you those extra few points in 3DMark. So you can either use a combination of slot 1, 3, 4 and 5, or slot 2 if you only have one graphics card.
In case you have four video cards you want to use, MSI put a little block of dip switches called CeaseFire, for individually disabling the slots so you don't have to take out the cards each time.
The XPower has two more USB 3.0 ports than the MPower, 12 instead of 10, and two more Serial ATA 600 connectors (10). Whether those are of any use to overclockers is another matter, but MSI wants to give you as much bang for your buck apparently. You get 7 instead of 5 PWM fan connectors, and 32 instead of 20 phases for the power supply. The XPower has DrMos chips, unlike the MPower (Max) which is equipped with PowerPak PWMs. The combination of the extra phases and the DrMos chips should make it possible to supply up to almost 2000 watts of power to the CPU. Like the MPower, MSI used the very powerful and efficient Hi-C capacitors for the CPU power supply, and they're so flat it leaves lots of space around the processor socket.
Another difference between the MPower (Max) and the XPower is that the latter has a PCB with 8 instead of 6 layers. It's one of the reasons this board costs more, but it should also allow for signals to be routed more efficiently. This should benefit extreme overclocking.
The XPower has more hardware features for overclocking. You again get + and - buttons for adjusting the bClk (in increments of 1 MHz or 0.1 MHz), and there are buttons for changing the multiplier. A new addition is the Complete Discharge button. It removes all BIOS/NVRAM settings, along with any data that's stored inside the Z87 chip.