By your own figures, you've spent $3200 on the 1070s but $3600 on the 1080s.
(the $400 and $600 are close enough I'm not going to quibble over the actual pricing, which is a very little less in both cases to go with the lowest-cost cards on Newegg on any given day).
*HOWEVER* your figure of 800K PPD for a 1080 appears to be HIGHLY optimistic based on the database at
https://docs.google.com/spreadsheets/d/1vcVoSVtamcoGj5sFfvKF_XlvuviWWveJIg_iZ8U2bf0/pub?output=html# (I don't have any 1080s so I can't compare based on my own figures), while that 600k figure is in line with my 1070 farm of VERY MILDLY overclocked 1070 cards but very PESSAMISTIC vs the database.
I think you're trying to make a case here based on BAD DATA.
- The pricing in that comment is using is his figures, not mine
Actually those were your figures. My figures were $550 and $800 CAD respectively (even though it's actually more like $510 vs. $780 for the cheapest dual or triple fan design but I was being conservative). I knew if I used my own figures you would nitpick everything.
@QuintLeo, the difference comes from the fact that you need an extra $400 for the rest of the components of each rig (One really good PSU like an EVGA 1300W G2 and then cheap/used everything else, milk crate or self-built wood/aluminum or whatever for case/chassis etc.). You only need one rig for 6 cards and two rigs for 8. I wanted to use his own example of the worst case for the 1070s where you need to pay for an extra rig and only get 7 or 8 cards to show that even in that worst case and with his overly optimistic 1080 PPD numbers, the 1070s still come out ahead. But of course it's still wrong because FLDC only pays out once a month lol.
But you're completely ignoring the fact that the guy with lower per-rig income would have 50% more of those rigs lol
Now, I'm sure you're still stuck on the "more cards" end of your thought so, remember this...
Cards 7 & 8 will need
another full set of hardware to run.
Ignoring the electric difference (~$15.77 USD per year for *total system* @ $0.01 per kWh):
GTX 1070
Cost: ~$400 USD
PPD: 600,000
FLDC per month: 12,000 - ~$14.72 USD
CURE per month: 787 - ~$35.43 USD
Purchase ROI: ~8 months "raw cost" per card
Yearly Revenue: ~$599 USD
GTX 1080
Cost: ~$600 USD
PPD: 800,000
FLDC per month: 16,000 - ~$19.29 USD
CURE per month: 1050 - ~$47.25 USD
Purchase ROI: ~9 months "raw cost" per card
Yearly Revenue: ~$798 USD
...
My figures weren't $400 and $600 - someone else came up with those, I just agreed that they were reasonable for comparison.
I never stated any figures of my own.
I wasn't looking at one WU - I was looking at the AVERAGES page - which points to your 800k PPD figure for a 1080 as being quite a bit on the high side of a FAIR estimate, and your 600k PPD probably being a bit on the low side, both cards being equally overclocked.
$400 seems quite a bit on the high side for the "additional base system" to me, but that's likely due to the fact I don't build riser systems.
Even if that figure is included, that would give you a second system that 3 cards could be added to before you need to do it again on the 1070 side, vs having to add a second base system on the 1080 side before you could add more cards - which would allow the 1070 based setup to pull away from the 1080 using reinvested profits.
Let's look at $8000 - 2 full 1080 rigs, 12 cards at 9,600,000 PPD vs 3 full 1070 rigs 18 cards at 10,800,000 PPD.
Interesting how a straight up FULL RIG comparison favors the 1070.
You see this same result at all price points that do not compare a "optimal price point for exactly full systems" 1080 setup to a non-full-rigs 1070 setup.
If the 1080 didn't carry a premium price compared to it's additional performance, it would win - but paying 50% more per card for 33% additional performance (or LESS using posted real world figures, probably due to the memory system not being all that much faster) overcomes the savings on non-GPU components in a FAIR comparison.
It IS interesting that the $4000 point was chosen for the comparison though, since it seems to be THE most favorable point for the 1080 - and the 1080 STILL ends up losing past the first month or two.