I find it hard to believe that the native resolution of your monitor is that high. try setting it where it should be........... and the 6770 on a 23 monitor makes no sense to me. lower everything if you want to play BF3.
That is a sweet monitor! My 23in Samsung is only 1920 x 1080. That monitor is also your problem. A HD5770/6770 is more a good card for 1440 x900 or 1280 x 1024. It is not up to 1920 x1080 gaming on anything but low/medium settings and is sure as hell not up to anything higher than that. To be honest even in crossfire you would be disappointed with anything over 1920 x 1080.
As I am sure you have figured out that is a huge step down from your old GTX 570. In fact it's about half.
Yeah, I noticed it was a really really bad idea!!! So I just got an eVGA 560 Ti Superclock from Amazon.
So I hope it is better.
The 560Ti is a huge step up from the HD6770 and will play most games at 1920 x 1080 on high settings. The bad news is you still have a super high resolution monitor. To be honest even the GTX 570 you had was on the low end for that high a resolution.
Sounds more like a work station monitor than a gamer. For something like that you need a card with 2gigs of vram...... 6950, etc. Too bad the 570 went belly up for you. would have been better. There has to be other resolutions the monitor supports. try lesser res. sounds like the only way out until you upgrade your card.