Well i have info about z68 + z77
[ as you all given Thanks for it ]
But just wanted to know why to buy z77 over z68 ?
There's no particular reason that'll always fit, because not all z77 motherboards will have the same features, and neither will all z68's. The minimum you'll always get with a z77 are a bit higher than with a z68 though - for example, all z77 boards will at least support memory up to 1600 MHz, while z68 guarantees only up to 1333 MHz. But the z68 board you linked supports way up to 2133 MHz, so obviously that's not really a factor in this case. The same goes with USB 3.0 - z68 boards aren't guaranteed to have it, but it's not like there's a law against supporting it, so high-end z68 boards usually have USB 3.0...
But i found out online z68 have all the feature that z77 have so why to buy z77 over z68 ?
The Z77 chipset allows native USB 3.0, and I believe (don't quote me on this) that it also allows for more PCIe 3.0 bandwidth in tandem with an Ivy Bridge CPU. Prices shouldn't vary much between Z77 and Z68, so choose which one fits your budget and preferences the best.
Also, while Z68's support Ivy Bridge through BIOS updates, the Z77 chipset was designed around Ivy Bridge. Basically, if you want Ivy Bridge and already have a Z68 system, you can just upgrade the CPU. If you don't have Z68 it is better to get the Z77 which is designed for the IB's
But i found out online z68 have all the feature that z77 have so why to buy z77 over z68 ?
z77 have PCIe 3.0 wic is only usefull if your going for a 5760x 1080presolution since the 2560x1600 do not bottleneck the PCIe 2.0
Also the z77 have the lastest version of bios.
All in all for the average guy the z77 bring nothing over the z68. Go for the cheapest one if your not going for a 2000$+ system and even at that point the z68 might bring anything that you need.
I did a little bit of research and found out that I was wrong about increasing bandwidth on the PCIe slots. It does, however, give a lot more support for onboard graphics when using the Ivy Bridge CPU.
"Another aspect of the chipset that has been improved is the support for onboard graphics. Once the matching 3rd-generation processors are out, motherboards will be able to offer three simultaneous monitor outputs instead of just two. Onboard graphics will also be faster, but both of those are functions of the newer processors; when paired with older Sandy Bridge CPUs, the speed will be the same as Z68 and the number of monitors supported at a time will still be two."
I almost forgot about the native memory controller as well (with Ivy Bridge.) Should support higher frequencies natively on most Z77 boards (again, with Ivy) now.
In a nutshell: There is very little difference between the two. Z77 has a few little things more than the Z68 so if you have a choice between the two and they are the same price point get a Z77.
Instead of deciphering what you mean, what system are you looking to throw together, THE UNKNOWN? If you post a CPU/RAM/HDD/etc list then we can find you a board that meets the specs, and other ones that exceed them if need be. Are you planning on upgrading? Do you just want general information? (Which has already been well-provided) Do you need a new one because one broke? Do you want to support a 600 series/ 7900 series GPU?
Well i have info about z68 + z77
[ as you all given Thanks for it ]
But just wanted to know why to buy z77 over z68 ?
You asked for the difference between the platforms, which have been explained to you many times in this thread.
If you are looking to buy one, get whatever you want, we can't make up your mind for you. But the differences have been very clearly explained for you.