The following should help.

https://www.dell.com/community/Optiplex-Desktops/390-GPU-upgrade/td-p/6156736

what is your question?

there are many low profile cards sold. ITX , each card has  spec, and manual that covers TPD needs.

every one..

what you are limited to is the lame SFF is slot power limited. 25watts ( read pathetic)

why not get  full sized, MT DELL and run any card you want. why invest cash in any 390 SFF ever?

what do you expect the card to do , no job stated, 3D what? name  something you can do now  or tell what you are attempting.

for all I know the 390SFF can NEVER DO THAT what ever THAT may be...

Imagine a MOPED going up PIKES PEAK.

fail/

why not spend $50 on a used DELL optiplex 3020 and have  a future. (hint get rid of the moped)

just advice, but many love dinky PCs with slow GPUs.  your call.

a GT1030  uses 20 to 30 watts, varies by maker. and ram size. and slow with filrates in the 20's (slow)

some ITX cards need 160watts. ITX does not limit power, like this old dell does. dell is not ITX

but ITX is what you'd shop. sure. 1030 is the most tiny and new. a good choice if it fits.

MSI is not the the only maker of cards 1 in 10 they are.  and all are different sizes.

The model you list DOES NOT FIT into Desktop or SFF

https://www.msi.com/Graphics-card/GeForce-GT-1030-AERO-ITX-2G-OC.html

Must use Dell or PNY or Gigabyte or MSI LOW PROFILE Single slot card. 

https://www.gigabyte.com/Graphics-Card/GV-N1030D5-2GL#kf

https://www.msi.com/Graphics-card/support/GeForce-GT-1030-2G-LP-OC

https://www.dell.com/en-us/work/shop/accessories/apd/AA362018

When installing an after-market graphics card into a Windows PC with UEFI secure boot enabled, the system may not boot.  This is true for ANY PC not just Dell.

http://nvidia.custhelp.com/app/answers/detail/a_id/3156

https://www.youtube.com/watch?v=2y32mBdZHJY

Dell A9763687

https://www.dell.com/en-us/work/shop/accessories/apd/a9763687

8CCF1 Nvidia GeForce GT 1030, 30w is for tower only or you have to make your own bracket.

PNY  VCGGT10302PB

https://www.pny.com/geforce-gt-1030

Dell A9763687

https://www.dell.com/en-us/work/shop/accessories/apd/a9763687

Here is similar SFF Vostro. 

https://topics-cdn.dell.com/pdf/vostro-3470-desktop_owners-manual4_en-us.pdf

https://topics-cdn.dell.com/pdf/vostro-3470-desktop_service-manual_en-us.pdf

DELL 3470

OPTIONAL CARD

Bro im very thankful for ur advice but just telll me if it can run on it please (yes/no)