R series cards REQUIRE UEFI bios and the 780 does not have this so the card will not work.

GT 1030 is 40w and will work in DT

1050TI work fine in the mini tower.

Nothing works in USFF.

There are no slots in USFF.

780 family

Like the Zotac Mini 1050 TI.  Must be a short card.

Radeon HD 2000 3000 4000 5000 6000 7000 8000 series work fine because they support DOS VESA Video mode 103 which the motherboard bios requires.

Thank you for your fast reply. Do you have a list of AMD cards that would work in the 780 DT that would also be good for newer games? I am attempting to turn my 780 DT into a small but respectable gaming box.

Thanks.

The Single Slot 7750 is a lot older than Geforce Pascal based cards.

https://www.youtube.com/watch?v=-ZvUnBYax_4

The GT 1030 GDDR5 card is the lowest I recommend. (STAY CLEAR OF DDR4 versions which are Junk)

Only the PNY 1030 works in DT

All others Require MINI TOWER.

NOTHING WORKS in USFF.

780 family

https://www.dell.com/en-us/work/shop/pny-geforce-gt-1030-graphics-card-2-gb-gddr5-low-profile/apd/a9763687/graphic-video-cards

ZOTAC GeForce GTX 1050 Ti Mini, 4GB GDDR5 (ZT-P10510A-10L)

https://www.amazon.com/d/Computer-Graphics-Cards/ZOTAC-GeForce-DisplayPort-128-bit-ZT-P10510A-10L/B01MCU1ERO/

You can put a 1060 1070 or 1080 HOWEVER the power supply will need a special MODDIY adapter and the case will need hacking because there are very few SINGLE SLOT versions of the card in the same style as the Zotac MINI.

Playable 1920 x 1080

https://www.youtube.com/watch?v=6ySet4Mh8gU

Using those cards must also be the SHORT versions.

The Moddiy Adapter is not optional.

You will also want an EVGA 750B1 power supply.

110-B1-0750-VR 

https://www.amazon.com/EVGA-SuperNOVA-Modular-Warranty-110-B1-0750-VR/dp/B00K85X23O/

The B2 BQ G2 models DO NOT WORK                                                                                                                        

https://www.moddiy.com/products/Dell-980-960-780-760-PSU-24%252dPin-to-Mini-24%252dPin-Adapter-Cable-%2810cm%29.html

Is it just the PNY GT 1030 that will work in the DT? I found the Gigabyte Low Profile Single Slot version for a much better price.

DDR4 or DDR5 version.  There is a reason that some of the models are "CHEAPER" and its not a good one.  The DDR4 vs GDDR5 version.  Gigabyte makes both.  The DDR4 card is 400 percent slower and only uses 20W vs 40W for the GDDR5 due to much slower Ram and Clock.

The Low profile GDDR5 cards are fine from MSI or GIGABYTE or ZOTAC or PNY or or or or

but BEWARE OF DDR4 versions which are JUNK HORRIBLE CARDS.

GV-N1030D5-2GL  Good card  30FPS

Gigabyte GV-N1030D4-2GL   BAD CARD 15FPS LAGGY

https://www.amazon.com/GIGABYTE-GeForce-GV-N1030D5-2GL-Computer-Graphics/dp/B071DY2VJR/

https://www.youtube.com/watch?&v=1CazEXejPCU

Thanks for the tip. The one I found was the GDDR5 version, with a small fan and heatsink. Thanks for all of your help!