Thanks for the suggestion.
Is the HX series better quality?
Quality comes with manufacturer and Corsair is very good with it through all its products.. HX is the suffix corsair uses on its PSU's to show that they are modular.. I believe all its PSU's have same attention to quality which is splendid by the way..
Here are the ATI recommended power supply requirements for the ATI Radeon HD 5770 and 5750 video cards:
450 Watt or greater power supply with one 75 watt, 6-pin PCI Express® power connector recommended
600 Watt or greater power supply with two 75 watt, 6-pin PCI Express® power connectors for ATI CrossFireX™ technology in dual mode.
The recommendations are for an entire pc system..
Corsair and Seasonic are two brands that have a reputation for high quality power supplies that consistently earn high marks in technical reviews. They are reliable, stable, and come with a 5 year warranty in the USA. Some of the newer models come with a 7 year warranty.
Here is a link to a list of Corsair power supplies and prices at newegg.com: