M/B came with bios v1.50 i upgraded to the latest (v1.90) and here are some serious issues that i come with:

After installing windows 10 my system never managed to boot again (screen stayed on windows loading for hours and hours with not doing nothing).

I decide to reinstall 8.1 everything worked fine except:

When going to bios and change something afterthat in windows my network card (intel) seems to be disconnected with some error on device manager (all drivers properly installed) after restart the problem not shown.

Also even a have disable fast boot form bios i must also disable it from windows because when i turn off the system and then power it on freezes on post screen (sometimes a blue screen appears and stays there).

After testing - unplugging some devices (peripherals and storage) i thought to roll back bios version.

I rolled back with version 1.80 and my system seems stable except the  fast boot feature that i must disable from windows . Also one thing i discovered is that my board have issues when i connect a USB hub on it (maybe it's USB hub fault - not tested a second one) . Also i have to say that i have not yet decide to upgrade to windows 10 , still with 8.1. 

Here is the rest of my system:

Case: NZXT H440

Cooler:Corsair H110i GT

CPU:Intel i7 5820K

GPU:Gigabyte Gtx-780 Ghz Edition

MEM:G-skill Ripjaws4 - 2133

PSU:Corsair AX860i

SSD:Samsung 840 EVO 512gb

HDD:Toshiba 2TB

Sound Card:Creative Soundblaster Zx

Mouse:Logitech G502

Keyboard:Raxer Blackwidow 2013 Stealth

Nevertheless the board except the above "strange behaviors" is pretty stable OC'ed @4.2 with max temps @50-60 C

I would like to share your experience , thoughts and opinions about these problems...

Thank you!