Hi @JACCKTG ,

Suppose your 3020 is a mini tower not SFF, it should be fine with RX 570.

Also, check out UserBenchmark: Dell OptiPlex 3020 Compatible Builds and you'll find builds installed with RX 570.

500w is too small.  EVGA 700B1 or 750B1 with MODDIY Adapter would be required.  Secure Boot must be OFF and Legacy Option Roms ON for the card to POST.

https://www.moddiy.com/products/Dell-OptiPlex-3020-PSU-Main-Power-24%252dPin-to-8%252dPin-Adapter-Cable-%2830cm%29.html

Only short versions of any card are going to physically fit into the case.

8.6 aka 9 inch long cards are a VERY TIGHT FIT.  10 inch Cards are IMPOSSIBLE as are 12 inch cards.

https://www.amazon.com/EVGA-BRONZE-Warranty-Tester-100-B1-0700-K1/dp/B018JYHBE6/

B3 BR BT BQ versions DO NOT WORK.

Only the B1 version works.

Single Fan Short cards fit and work fine.  Validated Cards from dell would be something like  AMD Radeon HD6450, 1GB, DP/DVI-I 3173K 2C7NH 02C7NH ATI-102-c26405(B)

https://www.amazon.com/Radeon-HD6450-Graphics-Display-ATI-102-c26405/dp/B07L5SVD53/

Hi thanks for responding very fast

so if I paired that Rx 570 4gb BUlK edition with that dell Optiplex 3020 . will i be fine? because i heard a lot of people talk about that (this is a comment of someone i found on youtube : No it wont boot since the rx580 and RX 570 only supports uefi bios and these types of old dell,hp, asus pc only have a legacy bios)
so is he right ? or taht rx 570 is just like any gtx 1050 ti a plug and play without any problems ?

Hi @JACCKTG ,

I don't have 3020 or RX 570 to test with. However, information from Userbenchmark are real-world benchmarks submitted by owners of this motherboard. Therefore you will be fine with this combination as well.

The 3020 has UEFI bios so this is a non issue.

HOWEVER secure boot must be OFF and Legacy Option Roms ON for the card to POST.

The non standard power supply means you have to use an adapter from MODDIY or some other vendor.

I have and use the MODDIY adapter and it works fine on my Dell  YMMV.

The physical Length of the card is another issue.

The issues are with the Power supply and the PHYSICAL size of a card.

Stock Power supply DOES NOT Support any 75W or greater card.

ONLY a tower can be upgraded with the power supply inside the case.

If you haven't purchased the system yet I would advise NOT GETTING a 3020 but rather a 9020 instead because the 3020 has a gimpy chipset and does not support AHCI so its really slow.

https://www.moddiy.com/products/Dell-OptiPlex-3020-PSU-Main-Power-24%252dPin-to-8%252dPin-Adapter-Cable-%2830cm%29.html

i have already purchesed the system, i have the mid tower, i test the size of that graphics card and it is fit insde the case and  what do you mean by 

Stock Power supply DOES NOT Support any 75W or greater card.

do you mean the small form factor ?

NO I mean the Tower.
The tower power supply is 290W
The Desktop is LESS THAN 255W
and the USFF has zero slots and is 180W

290 Watt Power Supply for Dell Optiplex 3020 7020 9020 Precision T1700 L290AM-00 PS-3291-1DF series, Compatible with part# KPRG9 KGF74 XFXKX 776VT

ok i understand 

i have as i told the tower version with 290 w, i will change the power supply to the one that is going to fit the case. 

will I be okay after that  ?

The PHYSICAL Dimensions of the card as well as the POWER DEMANDS of the card are the issues.

I looked up several RX570's and they are 9.5 inches and longer.

This is a problem unless you are going to hacksaw out the hard drive bays or move the guts to a new case.

Any NON DELL Power supply REQUIRES an adapter to convert the 24 pin cable to 8 pins.

EVGA GeForce GTX 560 Ti  P/N: 02G-P3-1568-KR    9" x 4.38" LONG

Requirements

Minimum of a 650 Watt power supply.   12v current rating 40 Amps miniumum

what about if I change the hard drive power cable to make it driven from the power supply that i am going to change instead of driven it out from the motherboard ?

because i tried to put my rx 570 and yes as you said, the card is a little bit longer but if i remove the HDD power cable is it going to be okay ?

The drive bays get in the way physically so no removing that wont help.

i tried to put the card in case and yes it fits the case and there is no problem with the physical issue it doesn t even touch the beys.

i will buy a power supply soon and if i have any problem i will ask you 

thanks my friend you are a really true life saver