The current 260w is not sufficient for 1660 Super.  Dell has 500w oem psu for 7090 tower.  Even the 360w oem psu will do.  Send a msg to Dell mod Chris M for part number of psu then use the p/n to chat w Dell sales for stock availability and pricing in your region.  Actually here it is Y7R0X 500W Chicony99TPH 500W Liteon5K7J8 500W Delta dimensions 85x65x225 mm Tower:260 W typical 85% Efficient PSU, 80 Plus Bronze 300 W typical 92% Efficient PSU, 80 Plus Platinum 360 W typical 92% Efficient PSU, 80 Plus Platinum 500 W typical 92% Efficient PSU, 80 Plus Platinum
Good morning,  I'm very new to the PC scene, and I'm finding it difficult to wrap my head around trying to find a compatible power supply. The current one in my 7090 towers is rated 260 w, and I'm looking for one that goes to 500w. One of the manuals suggests using a 1660 super GPU with this tower which I'm planning to do but I have no clue how to tell if a supply is compatible or not.  Thank you
Power supply compatibility