One 5830 will actually pay itself off in 2 weeks.
The 5830 averages 286 Mh/s in a survey of 20 of the entries on the Hardware Mining Comparison Chart.
The 5850 averages 236 Mh/s in a survey of about the same number of entries (can't remember now). That is an incredible difference!
I guess it can be attributed to the fact that the GPU used in the 5830 is the same one used in the 5870.
Right now Amazon has a 5830 for $154 and a 5850 for $161. Very small diff in price, but big diff in Mh/s.
5850 has 1440 shaders at 725mhz, 5830 has 1120 at 800mhz, how a 5830 can go that much faster?
I guess you read it wrong, 286 for 5830 and 326 for 5850
man, 5830 almost became mythical for being good for mining, but no, it's not faster than 5850 and the latter will stomp it any day at same or slightly lower clock.
Edit: a 5770 with 800 shaders can do 200mh/s and 1440 shaders does 236 is hardly believable.