What a day............ all spent trying to get a gtx-275 running on milkyway. Finally did it after ending up trashing a windows installation. Anyway the gtx-275 takes better than 10 minutes per cuda work unit on milky way compared to about 3.51 minutes on an ati 4850. And the 275 eats more juice also, and puts out more heat. So I don't know what the actual comparison is between the amount of work in an ati work unit compared to the cuda work unit. But if I had another 4850 or other double precision ati gpu around here I'd trade it out. I guess it's better than nothing, or crunching with the cpu -- :-) but sad to say that on another project now, the cuda doesn't hold a candle to the ati card. Sorta brings big crocodile tears to my eyes to as that 275 cost a pretty penny when I got it compared to what I paid for the 4850's when I got them.