As others have said, unless you game on a 144Hz monitor or at high resolutions, 1440p or 4K, there's no point upgrading your 480 right now. It's still an excellent card for 1080p gaming.
About the big difference in price between graphics cards with the same GPU, there are several reasons. Brand is one, of course, but others are the cooler used, if the card features an overclocked GPU or not and then the fancy things like lights.
Of those two ASUS cards you listed, the more expensive Strix has a much better cooler (that will also be quieter) and has a backplate that ads rigidity to the card and helps it to deal with the weight of the cooler. And some say that it also helps cooling that part of the card.
Please excuse my bad English.
Former gaming PC: i5-4670k@stock (for now), 16Gb RAM 1600 MHz and a GTX 1070
Current gaming PC: R5-7600, 32GB RAM 6000MT/s (CL30) and a RX 9060XT 16GB
Steam / Live / NNID : jonxiquet Add me if you want, but I'm a single player gamer.
