GPU Dell Optiplex 9020 mini tower

Using that 75W gpu requires the optional 365W power supply and secure boot off in bios.

365w PSU =
7VK45 365w, Huntkey
T1M43 365w, Delta

You have upgraded psu to 400w.

this card is 7.6” long, double slot width, no problem to fit inside 9020 MT.

Out of the box 3020, 7020, and 9020 have no more than 10 inches (25.5 cm) of free space for dedicated graphics cards. To be on the safe side the maximum GPU length you can use on OptiPlex 3020, 7020, and 9020 is between 9.5 and 10.0 inches. Everything above that calls for drive bay removal.

Also, 365w PSU is unnecessary for 75w card.

As long as it's a Dell PSU, the 290w PSU in the 9020, and another example, the 275w PSU in the 7010 easily power 75w cards.

1st screengrab is from the Tech Guide for the 9020, 2nd for the 7010:

Optiplex 9020 Tech Guide 

Optiplex 7010 Tech Guide  Regular size print:  I know this thread is not about the 7010, used for another example only.

30w GT 1030:

Non Dell cards use more power than OEM Dell cards which is why I do not recommend using 290W power supply when even nvidia recommends 300W minimum.

Using the 365w unit allows for updating to more drives and gpu and ram etc without pushing power supply to the brink.

  EVGA 500w is recommended in this case with moddiy adapter.

https://www.evga.com/products/product.aspx?pn=100-W1-0500-KR

There is also a guy who made his own adapter from scratch.

https://raphtec.wordpress.com/projects/dell-poweredge-t20-atx-power-supply-adapter/

MODDIY adapter  CAB359 is not optional with NON DELL power supply

https://www.moddiy.com/products/Dell-Inspiron-3650-PSU-Main-Power-24-Pin-to-8-Pin-Adapter-Cable-30cm.html

https://www.youtube.com/watch?v=SCQTj1ei3Ew

Not sure why you mention the GT1030 when OP asked about

"Hi, just coming here to ask if a Nvidia 1050ti 4gb GPU '

Have actually been looking about and double checked this card works with my motherboard, it requires a  PCI-Express 3.0 x16 interface, and on the 9020 manual it says I should have this, but I looked at CPU-Z and it says max supported link width is x8... I've attached where it says this. I'm don't know enough to be certain on this so could someone tell me if this will work if I was too install it. id be using it to play Triple A title games, just wanna make sure i don't spent the money for it not to work. 

thanks all 

Pascal based video cards work fine in 9020 models.

If they are not DELL OEM models then secure boot must be off.

25 to 40W cards are fine with the 290W psu

but 75w and up cards require the optional 365w psu

Re: looked at CPU-Z and it says max supported link width is x8

which video card do you have now that is installed in blue x16 slot.

 The blue slot supports max 16 lane.

PCI Express x16 data width (maximum) — 16 PCI Express lanes

the black x16 slot is wired x4.  Is it currently empty?

PCI Express x16 (wired as x4) data width (maximum) — four PCI Express lanes

which cpu do you have now?

for general reading why x16 gpu runs at x8

@speedstep ,

I know what the OP asked about.  You pointed out Nvidia recommended 300w PSU for certain cards.  So I pointed out they recommend the same for the 30w GT 1030, which is unnecessary for a Dell PSU.

i didnt think about that, ive got a AMD R7 200 GPU installed but wanted an upgrade for gaming... 

so does it only show that because its x16 is currently being used?

thanks 

If you have a R7 240 or R7 250 in x16 blue slot, only x8 lane is used because those cards are x8 in bus interface.  Although the card has x16 physical teeth, only PCIe 3.0 x8 bandwidth.

75W video cards and adding drives and ram can push 200 - 290W power supply to failure.  The OP asked about a 75W card not a 30W card.

The GT1030 is not of concern.

Power supplies are not a single spec of WATTS.

Combined power on the 3.3v/5v rails is important and its not just the PCI-E slots using that power.

PCI-E 3.0  X8 is the same bandwidth as PCI-E  2.0 X16

PCI Express 3.0 connection was specified in 2010, with a maximum theoretical transfer rate per lane of almost 1 GiB/s (actually, 984.6 MiB/s), twice the rate of the PCI Express 2.0 standard that offers 500 GiB/s per lane. Thus, a PCI Express 2.0 x16 slot offers a maximum theoretical bandwidth of 8 GiB/s, while a PCI Express 3.0 x16 slot reaches 16 GiB/s

although, it was helpful to me. i might just go with what they recommend instead of having to upgrade psu, etc. i only want to play light gaming.