thanks for your response guys.
i have another question,i wanna build a rig that contain's 4 asus r9 390x dc2 8gb and 1 rx 480 4gb
actually i feel fear when i think about this, i wanna spend alot of money and i am afraid of altcoins gonna be cheap in future. what shoud i do? is this predict possible?
mining of etc and zcash is profitable in future?
can you give me advise?
extra information: i spend nothing for electricity
better build 5x rx470 4gb rig.
"extra information: i spend nothing for electricity"
No reason to go with 470s at all. 390/390x is definitely the way to go with zero power cost.
I don't think this is necessarily true. I guess without power cost, maybe. But poster above is right. Beefier power supplies etc, make costs go way up. Likewise, try finding a 390 for less than 200, even used. Lowest I got mine for was like $185 out the door, but got lucky on ebay. $200 is more typical...
Figuring that in, it costs more per hash than RX 470's... Although it may be balanced out by having to buy more motherboards, RAM, etc... But for me, where electricity still matters to some extend, the 470's massively lower w/sol would be my choice... Just for anyone wondering what the better deal *might* be in their circumstance.
No. Going from 470 to 390/390x on a 6 card rig will require at most an extra 700W. That's a $100 PSU. If you don't think spending $200 ($100 PSU, $100 or so on GPU's) more to bump hash rate by 40%+ on free power then you shouldn't be building a rig to begin with.
Already without the latest update promising even more hash/s on 390/390x they run close to 50% higher than 470s so with NO power cost. It's a total no brainer if you are building a rig.
For one, an increase on Claymore miner's hashrate means difficulty goes up because everyone gets the increase. Second, yeah, if you are not paying for electricity, I can see the appeal of R9 390's. But 300 sol/s for 300 watts (ususally hashrate never gets that high...) vs ~210 sol/s for 100 watts sounds like a better deal to me. Well, mostly if someone were only building let's say, one 6-card rig. But I did make an error before. I guess when you consider not paying power, and also the additional cost of motherboards, cpu's, ram, etc, then the cost of a bigger PSU probably puts you under budget for the same hashrate... So I guess I didn't think about it all the way through.
Don't worry, you're both wrong.
With free power the only way to go is Fury. $260 for 315 sol/s out of the box on 15.12 drivers. On 16.xx you can get ~350 sol/s with an undervolt and GPU overclock, but admittedly it is less stable.
Worried about power overhead? Buy a cheap server PSU dedicated to the cards. Problem solved.
Edit: Even if power is a factor you can run Furys on 16.xx driver with an undervolt and underclock to get ~300 sol/s @ 150W. That very nearly matches the efficiency of the RX series but nets 50% more hash for 25% more retail cost.