Bitcoin Forum

... 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.

Generated two blocks today on my 5970 :D
Maybe I'll get an extra one before difficulty skyrockets, you also get free heating with these littlefat marvels

don't forget, that within those 40days the difficulty will rise, so if the price of bitcoins stays at ~$0.2, it might take slightly longer for the card to pay off.
besides that, the 5850 isn't a bad deal, ~230Mhash/s at default clock, ~300Mhash/s overclocked.
if i had some less expensive energy, i'd just buy some more. :D