No the 580s are for gaming, folding, video work and daily use.
Nonetheless, I doubt mining is even profitable, for the electricity cost of leaving them on.
Hmm.
One 580 is giving me atm, 150MH/sec
Let's say 300w draw for card. That's 7.2 KWH/day or 216 KWH per month x $0.10 here or $21.60 a month.
If one 5970 generates roughly BTC 0.48 a day for ~720MH/sec, let's just divide by 5, so that'd be roughly BTC 0.096 a day x 30 days (keeping it simple here) = BTC 2.88 per month. 2.88 x (we'll say $5) = $14.40
...
DARN IT.
To be honest I'd sell the card and go AMD if their drivers