They eat too much electricity compared to their hashrate. I wouldn't bother.
They still might be profitable considering the high profitability of zcash at the moment and the shortage of new cards.Yes, but barely. Why waste so much on electricity and gain small profits instead of buying a modern card?
I could only find one number on the 780 (non-Ti) which apparently does around 98-103 sol/s. Assuming that number is about right, for a card with ~250-280 watt consumption you're looking at $0.5-$0.6 profit a day depending on electricity prices.
A single 1070 nets you 10 times that.
You might get that much, but I couldn't find info on it.
