And even more if the prices goes up.
That argument works both ways. But by the very nature of Bitcoin the price should certainly go up.
In my humble opinion, anything that requires more than 2/3 months to pay the initial investment isn't not worth it. Difficulty is increasing which will extend those 8 months indefinitely.
Also: the 7000 series should be out soon and your hardware will become outdated.
PS: here's a calculator that
estimates difficulty to help you with your choice:
http://forum.bitcoin.org/index.php?topic=26751.0That's what I was thinking. If it takes over 8 months to pay off then is it worth it. Considering when I do start taking profit it won't be much.
Maybe I should wait for the 7000 series, but to be honest they would have to use 50watts a piece to make them profitable in my part of the world.
If the hash rate increases it would just be cancelled out by a rise in difficulty due to blocks being completed quicker across the network.
So realistically, unless electric comes down in price or Bitcoins increase in value, this isn't a valid investment opportunity really is it?