Thanks for the helpful math and bump, Matthew. Guess you didn't get what you were asking for yours (hence the thread spillover/you looking to troll all 5830 postings), or you are tooooo cheap, and/or are looking for handouts.
Last I also checked, they do any proof-of-work thing, including mining bitcoin, namecoin, buttcoin (among others, all with diff exchange rates), along with, I don't know, graphics rendering.
Two late model, crossfireable, most games-on-absolute-max, graphics cards are always handy, regardless of the current absolute bitcoin mining and exchange rate, and a lot better than someones nVidia-hashing-getting-nothing-or-WoW-on-Low.
Next time, also link where the 5830 sits among the other cards (comparatively pretty high at low price/good btc hashing). Unless someone wants to drop $300-$600 per card, these are a sweet deal (latest was $100 for both).