... is an ATI Radeon HD 5970...
Anyone else putting graphics cards on their Christmas lists for some serious mining?
Actually the 5970 is a little pricey, newegg.com has it from $500 to $1200 dollars. But even lower end cards should be able to generate a few blocks a month hopefully.
Somewhere I got the idea that the number of "stream processors" would be proportional to hashes/sec. Probably clock rate would be proportional too. So I've gone through and divided # stream processors by price to get a "bang for the buck" measure. The 5970 has 3200 stream processors so the $500 card would have 6.4 processors per dollar. Actually most of the Radeon cards are in the 5-7 ratio so for the most part you get what you pay for.
The best ratio I found was for an HD5850 which has 1440 stream processors for as little as $200. That gives it a ratio of 7.2 and the price is closer to my budget. This has been reported at
http://bitcointalk.org/index.php?topic=1628.msg24699#msg24699 to get as much as 300 Mhash/sec. At current difficulty the calculator predicts a block every two days.
With bitcoins at about $0.20, a block of 50 is worth $10, so after 40 days the card would be paid for. That may be a little optimistic (especially if everyone gets 5850s for Christmas) but at least it would be fun to be generating blocks.
