what's the best gpu i can fit in my pc

[User]

i have an optiplex 9020 sff 255w
i currently have a gt 1030
i have several questions

1. what's the best gpu i can fit in my pc (with a new power supply to support it, since 255w supports very little)
2. is there a way to fit a gtx 1660 and a new power supply to support the 1660?
3. i have the default ram/motherboard from the optiplex 9020 sff and an i5-4670, should i expect any issues with a gtx 1660?

 

[Azdog]

to check compatibility just use PCPartPicker

 

[User]

to check compatibility just use PCPartPicker

Half the stuff I have isn't on there, including my case, motherboard, and power supply.

 

[Kuchy]

Half the stuff I have isn't on there, including my case, motherboard, and power supply.

Same issue with me. I usually look up stuff with similar specs like case size and motherboard ports.