Yes 1660S recommended psu is 450W. Dell 460W psu should be good. dell sells 1660ti which is a tiny bit faster than 1660S.  If you want to buy your own 1660S just make sure its size fits the case. Dell also claims 2070S is supported but this card has a recommended psu of 650W. Not sure how a 460W psu can handle it, unless Dell OEM card is sub spec. by the way, Vostro 5880 uses same new 6 pin ATX and 2x 4 pin 12V CPU on motherboard also seen in G5 5090 and XPS 8940.  These new Dell beasts share same design DNA.  The pinout has been worked out allowing possible psu upgrade.
I have the Vostro 5880, with the following specs: -I7-10700; 16gb ram; 2tb hdd; 256gb ssd; optical drive combo I was wondering if the 1660 super would work in this machine, as the dell website says the vostro 5880 can support anything up to the RTX 2060. The 1660S is a rather power efficient card, and with the listing of the 2060 model it makes me confident that this can work. I would certainly appreciate your comments and thoughts on this endeavor though, because I am still quite unsure. Thank you New Vostro 5000 Desktop | Dell USA  
Can the Geforce 1660 Super be added to the Vostro 5880 with the 460psu provided?