Tong Family

Well the big news is that you fit this monster Core i7-3770K in just a tiny motherboard based on the Z77 or you can a big board with room for 4 graphics processors all based on the same firmware. The summary is the size of the board depends on how many graphics cards you will have:

• 1 GPU. Use mini-ITX. These boards are just coming out, but the Gigabyte Z77N-Wifi is a good example or the ASUS Maximus GENE Z77. These are just coming out in Z77, but the Gigabyte GAZ77MX-DH3 is an example and more are coming.
• 2 GPU. Use ATX or micro ATX with water cooling.  If you are OK with a bigger system because you need the space for big graphics cards and water cooling blocks, etc then the ASUS P8Z77-V Deluxe (Silver Award) has better software for overclockers. If you are going to go with water cooling or a dual GPU board like the GTX690, then you can use a micro ATX board. See Tom’s Hardware for such a build
• 3-4 GPUs. These are monster boards for dual monitors but the ASUS P8Z77-V Premium or the Gigabyte G3.Sniper 3 (Bronze Award) are both good

Z77 in mITX
Using the so called mITX standard, I just can’t believe how small a chassis this thing fits in. So instance the Gigabyte Z77N-Wifi has a SATA/mPCIe slot and plus dual gigabit ethernet. That is pretty amazing and a wonderful way to build a single graphics card machine

3-4 GPUs on Z77 ATX Motherboard
There are the first generation of Z77 boards which have multiple GPU support that really have enough bandwidth. A vanilla Z77 chipset has 16 lanes of PCIe (you need really 8 lanes of bandwidth), so you can see it naturally supports two GPUs are full speed. To get more lanes, there is a magic chip called the PEX 8747, you use something called PCIe bus switching to double those total lanes from 16 to 32. And you need enough extra slots as well. Most of them support three GPUs easily and have slots for four. The winner in this round up was the Gigabyte G1.Sniper 3. What a name by the way. Having multiple GPUs is super expensive and requires things like water cooling and even dual power supplies because the graphics cards eat up so much power. So this is the hairy edge where you want multiple monitors driven at high speeds. Cool!
So for instance the ASUS P8Z77-V Premium which is super expensive at $500 with lots of features (like an onboard 60GB SSD for disk caching, Wifi, Bluetooth, Thunderbolt and some really cool tweaking firmware like autooverclocking and auto fan speed control) and most importantly 4 GPU support.

Scaling-wise, the benchmarks show that you double performance roughly going from the HD4000 on board the Core i7-3770K to a GPU like the nVidia 9770. And that adding another GPU basically doubles performance. That’s the sweet spot of good performance. Going to 3 adds about 50% of a GPU and going to 4 adds about 25%. So you really need 3 or 4 if you are going to multiple monitors more than anything else

Here performance doubles adding a second graphics card:

The you get about 20% by adding another card (about 50% more power):

Then even more diminishing returns. Now this is for a 2440×1400 display, so the main issue is that with more pixels (like three monitors) a quad GPU will definitely make a difference but not for a single monitor:

 
MicroATX Z77 with 2-GPUs
If you don’t need more than two GPUs, then a microATX board makes some sense as it is smaller and less bulky. The Gigabyte GAZ77MX-DH3 is a good example. Like all Gigabyte it defaults to overclocking. It doesn’t a kazillion SATA ports but that’s not that important on a gamer PC. The main issues are the software that gigabyte has for fan control and so forth, but this is a nice form factor.
ASUS also has a dedicated overclocker line called the Republic of Gaming and their equivalent model is the ASUS Maximus GENE Micro ATX Z77 Gaming Motherboard (who comes up with these names anyway???) which pureoverclock.com really liked. The main problem with these microATX boxes is that because of size it is hard to get two big triple width cards in there, so an ATX is definitely more comfortable and likely to stay cooler and as you can see with a huge fan and big AMD graphics card there isn’t much room.

Z77 boards for ATX 2-GPU
There are literally a hundred Z77 boards and the main difference appears to be features for the standard dual GPU setup. the P8Z77-V Deluxe at $250 looks like the same design as the P8Z77-V Pro which is a 2xGPU machine with dual band Wifi, HDMI and Displayport, a zillion SATA. The P8Z77-V Deluxe got a silver award for 2 GPU systems. So even sticking with one vendor ASUS, there are literally a dozen different boards to choose from. And confusioningly the P8Z77-V Pro also has ASUS Premium Service and mainly seems to lack Wifi (not that necessary) in most desktops and has thunderbolt.
In a round up of lower end motherboards based on Z77, Anandtech found they were all OK. The key features appear to be with ASUS and Gigabyte, they have multicore enhancement and auto overclocking but Gigabyte has tweakier and more clunky firmware. So its a hard choice.
The punchline is how well these boards handle the same overclocking, you want a board that has lower operating temperatures there. From this you can see the ASRock Z77Extreme6 and the Gigabyte Z77MX-D3H are running really cool with the ASUS P8Z77-V Pro right behind it. The Biostar TZ77XE4 also isn’t bad.