I'd say wait. Your 4890 was a top card of its day. You would need to jump on a top card two generations later in order to really feel difference. You should go for 6950 at least in order to really make this worthwhile.
It sounds like you're more annoyed with the fan sound than actual performance. if u can get a good GPU fan, you may want to look into that. Or introduce some fan to move the hot air out of the case better.
It sounds like you're more annoyed with the fan sound than actual performance. if u can get a good GPU fan, you may want to look into that. Or introduce some fan to move the hot air out of the case better.