If you run it 24/7, anyways the cost of electricity will be much more in a year or so. If you run it sparingly, within some time cloud based 30 series will be launched for sure.
What is the price of electricity where you live? For me to pay as much as the card is worth in electricity, even running it continuously, it would take 11 years.
Granted, electricity is exceedingly cheap here, but still, 11 years is a long time.
Granted, electricity is exceedingly cheap here, but still, 11 years is a long time.