Question about NZXT H510 Elite

It works and I have also installed it this way, but I can't recommend it unless you really have a good airflow. Since I have the radiator at the front with the fans, it draws in too little air.
Temperature in facts:
-temperature when gaming in vertical state -> 85deg.
-temperature when gaming in vertical position and open window -> 63 degrees

Oops. You can see it in the pictures. It works :)

...only a 2 slot GraKa. :)

But I wouldn't recommend it because it's too close to the tempered glass and therefore doesn't get enough cooling and you have to accept a 30% loss in gpu performance.