I believe the h700i doesn't have a vertical mount solution. But with some modding you can fit one.
https://www.reddit.com/r/NZXT/comments/7aq4n9/h700i_current_build/
Can you list the parts he used for the build? Include the 3 cards he used. When you mean freeze, do you mean a blue screen then reboot, or screen on and the mouse and keyboard stops working etc.
Also are your games installed on the sdd? and if so how much space do you have left on it? BTW fallout is know for frame drop issues. Bad game mechanics.