A SFF 5070 with integrated graphics most likely has a 200W PSU. I would plan on upgrading if you're dropping in a GPU. Keep in mind I believe your system has a TFX power supply not a standard ATX power supply. With the SFF you'll want to make sure your GPU is low profile enough to fit in the case. I don't have much experience with that specific system but I hope this was of some help.

Thank you for the response, I guess I will just have to wait for it to arrive to see about a PSU swap. You’re right it’ll need to be a TFX PSU but I’m not sure what connections it will need yet. Thanks again!

Thank you for the additional information about the MB, now I know what PSU I need to look for in order to upgrade!

You're welcome.  : )

I don't know how standard it is among TFX PSU's, but among ATX, and some Dell MB's, 24-pin+4-pin is pretty standard.  24-pin to 6-pin adapter 

If you're not confined on space, it's easier to upgrade towers.  Granted Optiplex MT's are no longer full size and also take smaller PSU's, check out the PSU list for the 7080 from the spec sheet.  In the image, MT is the list on the left and SFF on the right.