Hey OP, can you describe the symptoms of your GX2? About half the time, there is a very simple fix for them when they die.
Also, if you are looking for a card that will be an upgrade, you will need no less than a 5850. Anything lower will be a pretty massive downgrade.
Originally Posted by GibsonSGKing
Yup. Remember, the 5770 is absolutely crippled by it's memory bus
It actually is, but this is only noticeable at hgih resolutions or in games that depend almost entirely on memory bandwidth (think crysis). My card gets near linear performance increases based off memory overclocks.