Hi:
I can't answer your question directly but I don't think it is a good idea.
The card should work as far as compatibility.
I have the lower power GT 1030 in my older 8200 Elite CMT and it works with no problems at all.
Here is why I believe it is not a good idea...
The recommended power supply for the card is 300W. The P/S in your model is 240W. I don't see that in and of itself, as a major issue.
The two things I see as major issues is:
1. The card draws 75W which is a bit much for the 240W P/S.
2. What I consider the worst thing, is that the PCIe x16 slot in the SFF is only rated to handle 35W, where in the CMT it is 75W.
So, putting more than twice the wattage draw on the PCIe x16 slot could result in a motherboard failure over time.
See the quickspecs below, page 14 for the slot wattage specs.
http://shop.itema-pg.com/userfiles/editor/file/HPCompaqElite8300BusinessPCDec2012.pdf