Its crazy to believe that so many people are still using the Tahiti's according to this thread.
Basically if you got a Tahiti you are better off mining XMR at the moment.
Reason why is because those you can reduce the voltage to the min value of 0.950V and if you got a decent ASIC quality you can run them at 1000/1500 core and you will get like 600H/s and it will only use like 130 Watts of power.
With ZEC it always used almost 200 Watts or so. With ETH it used even more electricity. The worst was Scrypt which was like 350 Watts per GPU from the wall.
You are absolutely right! CryptonightV7 is way better for 280x's now and it allows better undervolting than with the other coins. There are 2 things however. Basically if you got a Tahiti you are better off mining XMR at the moment.
Reason why is because those you can reduce the voltage to the min value of 0.950V and if you got a decent ASIC quality you can run them at 1000/1500 core and you will get like 600H/s and it will only use like 130 Watts of power.
With ZEC it always used almost 200 Watts or so. With ETH it used even more electricity. The worst was Scrypt which was like 350 Watts per GPU from the wall.
First, cards that can run on 1000 core with 0.950mv are of excellent ASIC quality and very rare - may be 1% of all. For example, my XFX's can't be even recognized by the OS if I undervolt below 1144 mv with 1000 core (well they do, but with several restarts and auto switch to 850 core). My Sapphire's are better, but still require 1050 mv to run with 1000 core. In both cases I got 170-180W from the wall. With 1000 core I get 460 h/s and with 1100 - 540 h/s. So the current profit of all coins now for me is 0. I also mine and stack the coins for future sale.
Second, Monero has 2,2 billion market cap and hardly will make 10 or 20 billion in forseeable future. Of course, who knows, if Bitcoin goes back to 20K this can happen someday. But the new coins have potential of making 10-100 and even 1000 times increase (fresh example zclassic, which made 1000 times in several months). So it is good to have more options. I try to mine as much coins as possible.
EDIT: Surprise, surprise. I just tested with the wattmeter. The XFX cards with 1144 mv are mining XMR with 140W, not 180W as I was expecting provided that 950mv mined with 130W. Equihash is around 200W.
Its weird because I got some Asus R9 280X with various ASIC quality levels and all of them run at 0.950V @ 1000 Mhz core. They hash at like 590 H/S.
I think the power for each card is like 120-130 Watts or so.
I had issues with some Radeon 7950 GPUs with the Elpida memory, those had stability issues at 0.950V and the memory was crap and it ran at like 500 H/s max, which is what my R7 370 can do pretty much.
Might as well run these GPUs into the ground.
