Due to the new difficulty coming in 2 days, my mining rig (3 x 5830) will cost more power as BTC revenue.

It will be cheaper buying the coins ...

for information:

Power consumption of the 3 cards 300 Wh ( about 35 euros / month)
With about 900 Mh I get (now!!!) 0.7 BTC /month = 60 euros *0.7 = 42 euros.

game over!