Newer 30xx and 40xx series Nvidia graphics cards (probably AMD cards as well) pack a punch, but with that comes extra size & weight.  Most PC cases do not come fitted with GPU support hardware.  This adjustable model should work for most ATX or smaller PC cases.  From base to tip is 110mm (~4.3 inches).

Prints as three pieces.  Can confirm that using variable layer height on the Base part at the point where the rod starts will work (saves time).  Otherwise, the provided gcode file is using the Standard Prusa Slicer "0.15mm SPEED" setting with a slowed down first layer, 3 perimeters, ironing on base top layers, and 230 degree nozzle temp.  Base has cavity to accept 18mm diameter by 5mm thick round magnet (see pictures).  With most PC cases, this base piece will be resting on metal, so the magnet helps provide additionally support.  The downward force of a GPU is likely sufficient to hold the piece in place. 

An adjustable clip slides along the rod portion of the base and can be secured at a specific position using the printed screw.