The Gigabyte Z77N-WiFi really isn't designed for hardcore overclocking. There is definitely some available headroom with a VRM capable of at least 125 Watts; however, there are no voltage adjustment options in the BIOS, other than to vDIMM. This means that you are left without the ability to adjust the CPU voltage, which is going to limit CPU overclocking in most instances. As I mentioned earlier, Gigabyte hasn't built this product around the gaming market, and the inclusion of Intel's WiDi is another indication of this. Gigabyte made it clear to me that this product is meant for business users, and long-term reliability being such an important facet of this particular market segment, voltage options weren't included to ensure that the VRM wasn't stressed through the use of a SandyBride CPU. Most IvyBridge CPUs will reach 4.5 GHz below the 125 W mark(my test CPU does 4.5 GHz with 83 watts or less consumed), so there is some headroom, but not enough to compare it with other full-sized board products when it comes to CPU overclocking. Multiplier adjustments are possible in the BIOS, but what VID is available will probably depend on each individual CPU.
Memory clocking, on the other hand, works perfectly. My G.Skill test DIMMs easily booted 2666 MHz by simply enabling XMP, as you can see in the screenshots above. As with other Gigabyte products, a custom CPU Turbo profile bringing all cores up to 3.9 Ghz is also enabled once XMP has been turned on. This is a small performance boost, and one I didn't feel was worth showing in graphs, since it will only match some other boards using "stock" settings. There's some extra performance available, but it is not a lot.
With only small performance gains to be had, some may be disappointed, but to me these gains are perfectly acceptable. The small size of the board can only allow for so much and had to be expected, this being the most affordable Intel Z77 Express mITX board on the market, especially given its additional features. I play BF3 online every day, and BF3 is one of the more demanding titles available right now. The limits imposed by the design of the Z77N-WiFi don't take anything at all away from my BF3 gaming experience. Very few games really NEED a CPU overclock to perform well unless you have an under-performing VGA, and the Gigabyte Z77N-WiFi is, as a gaming product, best paired up with a high-end VGA, such as an AMD HD 7950 or, perhaps, a reference Nvidia GTX670. Combine all that with some watercooling, and you can have a serious gaming box with a tiny footprint, and tiny power consumption.