Unfortunately you can't really go by shaders per dollar. For example the 390 is only a few Mh behind the Fury X even though theoretically, the FuryX should be around 50% faster. This is likely just an optimization problem but that's how it stands.
The 4GB 380 was the best value card up until last week but prices prices crept up enough where the 380x is probably now the ideal card if you want to get your feet wet. I still think if you're going to spend the money the 390's make the most sense to buy. Sure they'll take a little longer to get your ROI, but after that it'll earn at a 40% faster rate and hold better resale value. Fewer cards to manage as well.
It'll take six 380's to match the speed of four 390's. The added expense for connectors etc is not really worth it if you're trying to scale to higher speeds.
I'm at 225Mh now but stopping here unless I can figure out a way to get cheaper power. My cards should all provide a ROI well before Polaris hits. Luckily I had enough other equipment where I only had to buy a few connectors and cards. If you have to buy everything it gets expensive fast.
That's really interesting on the Fury's. I wonder why they perform so poorly? The other GCN chips (Pitcairn, Tahiti, Tonga and Hawaii) all seem to track pretty much right on with shader count. Perhaps there's something in the algorithm that just really doesn't like the 500Mhz memory bus.
I have two Fury X's on my HEDT system. Combined they give me approx 60-65Mh while overclocked and undervolted. Even though they perform poorly the Fury's are better from a power efficiency perspective over Hawaii (especially the Nano) but unless the price of Etherium goes back to a few bucks and you're paying more than 15 cents per KW this really doesn't matter too much right now. Hence why I still recommend 390's as the best overall buy.
Perhaps it has something to with the algorithm itself as Bitcoin and Litecoin scaled really well with more cores. Maybe 4GB isn't enough for 4096 cores? I really don't know but I would love it if a new miner came out and took proper advantage of my Fury's although in another month they'll have paid for themselves if the price of Eth stays put and difficulty goes up as predicted
I haven't noticed any difference in memory usage between my 290, 7990 and 7950, all around 1.5GB.
Here's a question for the more in the know guys, is it possible the DAG could grow, and eventually exceed 2GB?
The DAG is increasing at a steady rate.
https://github.com/ethereum/wiki/wiki/Ethash-Design-Rationale
2GB should be insufficent by year's end, however with the switch to PoS (Proof of Stake) coming, there won't be a need to mine by sometime next year.
Nice powersupply. It could handle 2 390's pretty easily. Yes stay away from the 2GB cards unless you can find like a 270x for under 100. Too risky with DAG growing.
So is there no set date or time frame for when it will move to Proof of Stake?
Folks with 280x/7970 who mine 22-25MH / card, which driver are you using?
Well I had to flash back my unlocked powercolor 290 back to default shaders from 290X, which I had in the 2nd comp. Seemed to mine fine, but was getting some artifacts in games, and had a few display driver crashes. Mining on it now, still getting about the same hashrate, around 26MH/s
How often do you guys get the "failure: GPU returned incorrect result" message, if ever, when submitting to your pool? I happened to catch my mining window throw it a few days ago so I've been logging the window and investigating my overclock on my 290 since. Last night I ran it at stock speeds and voltages overnight and it still threw one about 6 hours in. It's a used card so not sure about the history, but maybe it's normal and just a part of using consumer GPUs or a small bug in the code.
Otherwise I can bump the card an extra 100MHz or so while dropping core voltage about 40mV and it seems fine, and runs a little cooler that way.
You can do voltage. Not sure how on GCN 1.1/1.2 though. Look, here:
http://epixoip.github.io/od6config/
It's a tool developed for Hawaii linux overclocking. I don't think you can do voltage with it, but you can do power levels.
Thanks. Whether or not I'll use it with 390s remains to be seen, though they are curiously good at mining compared to Fury/Fury X. If I feel like being a big(ger) spender then I might invest in 390s at some point.
I'm not worried about the DAG growth now that I know that 2Gb cards will be good until at least December. There are some 2 Gb cards I found that should pay for themselves relatively quickly and get me at least a little something before it goes PoS. I might expand to something 4 Gb or 8 Gb later if I like how things are going.
One interesting side-effect of DAG growth: a lot of mining capacity will go offline in December!
Well I had to flash back my unlocked powercolor 290 back to default shaders from 290X, which I had in the 2nd comp. Seemed to mine fine, but was getting some artifacts in games, and had a few display driver crashes. Mining on it now, still getting about the same hashrate, around 26MH/s
someone could build an ASIC before then rendering all cards obsolete.
setx GPU_MAX_ALLOC_PERCENT=100
setx GPU_SINGLE_ALLOC_PERCENT=100