I have seen similar threads but throughout my searches I haven't seen anything that mirrors my situation. I have tried numerous times to re-install both Server 2012 r2 and Windows 8.1 to enable hyper-v, I get the same issue every time.
In Windows 8.1 I can get Hyper-V to install but every action I try to perform, such as opening Internet Explorer or even switching from the desktop to the start screen takes literally minutes sometimes up to 10 for me to see any response. In server 2012 r2 I can not even log in and get to the desktop most of the time it hangs either at the Windows logo screen and the one time I did get all the way to server manager the hyper-v role showed in server manager but says the installation failed. I have had SOME luck but not much getting into safe mode in server 2012 r2 after the install.
I have an i7-3770k with a DZ77GAL-70K motherboard and contacted intel who apparently put together a test machine with the same specs and did not have any issue. The only similar threads I have seen refer to Gigabyte boards with USB 3.0 (which I disabled as a test) and the Azalia codec so I disabled the onboard audio with no resolution. I have tried before and after installing all of Windows updates for 8.1 and server 2012 and intel drivers with all the same outcome. Any help would be greatly appreciated!