I've got a 6870, and it mined about two LTC/day before the difficulty went up very recently. Maybe 1.5 now. That's about $4.5/day at current rates (which are currently falling).
It's all very uncertain, so don't expect to get a positive return on your investment. You might. You might not. It's a gamble, and calculating the odds is nearly impossible
As for your other questions: the wattage is fine, the other hardware isn't important, Linux is fine.
It's all very uncertain, so don't expect to get a positive return on your investment. You might. You might not. It's a gamble, and calculating the odds is nearly impossible
As for your other questions: the wattage is fine, the other hardware isn't important, Linux is fine.