POWER SUPPLY and CASE.
The restrictions are based on the Slot length.
MINI ITX versions of cards are fine but 10 to 12 inch long cards are not.
Cards over 75W require upgraded power supply and the MODDIY Adapter.
thank you for your responses.
If I upgraded my my case to a Fractal Design 1000 (which support graphics cards up to 350mm in length) and my power supply to a crucial cx 430w, would I be able to install a radeon rx 480 or gtx 1060? Or are there any restrictions to what cases the motherboard is compatible with?
Outside of the actual Dell case I am unaware of any restrictions other than the MODDIY adapter which is REQUIRED because the stock power supply does NOT support a card over 75W. Standard EPS12v power supplies have 24 pin connector and the motherboard has Dell connector instead. You also have to use the stock Dell cooler and front panel connections or there will be other errors that prevent POST and BOOT.
Replying to this thread as it's top of the google hits.
I have successfully put a Zotac GTX 970 Dual Fan (an 8" card) into the Dell 9020 MT.
It needs an uprated PSU and an adapter cable (24-pin ATX to 8-pin Dell). The PSU must be short case IE 140mm. I used a Fractal Integra M 750W which is a perfect fit and the case spring clip holds in place.
The 9020 also allows for dual SSDs in RAID0. It makes for a small, understated and quiet gaming rig. With the i5-4590 it benches slightly better than most other builds in the same class.
It looks like the physical clearance for the graphics card would allow up to 26cm (10" cards), but I have not tested this - yet. I have my eye on the yet-to-be-released Zotac GTX 1070 mini (210mm) for this case.
If you don't mind doing a hack job you can cut the 3.5 hard drive bays out and put longer cards in. The Drives can then be mounted up top in the optical drive bay area or in the other drive slot area.