My current config is:
Abit KN9 Ultra+Athlon 64x2 4200+ (2.2 GHz) 1MB Cache
2x1GB DDR2-666 which I plan to replace by 2x2Gb DDR2-800
Nvidia 7600 GT, 256Mb (which I use mainly with the proprietary driver, I find the performance of nouveau not too bad, however it is not stable enough).

I plan to change my graphics card and to use the free driver. I am looking at an HD6770, 1Gb. The performance on R600 as seen on phoronix benchmarks seems very good to me. However these benchmarks are run with much more recent CPUs so I am not sure what to expect for the performance on my system. I don't plan to run commercial games but I would still like to be able to play something of the level of 0AD or Lugaru HD. Do you think I will get a decent performance or that my CPU will not allow my HD6770/R600 to get much more performance than on 7600GT/Nouveau?

Also I am interested on how good is the multi-screen support? I have seen HD6770 cards with 3 ports (HDMI+DVI+VGA). Can I use any combination of 2 ports out of the 3 for a dual screen configuration with R600?

Overall should I expect a good stability with the free driver?

Thank you.