I wish you had asked a week ago - had 2 short power "glitches" this week.

 My A2 rigs routinely post multi-month uptimes - limited by "have to shut them down to move them", "power outage dropped them" and lately by "swapping pool for better profitability".

 I think my 3-card R9 290 rig was in the 3 month range just before last week's "power glitch", it's been amazingly solid (though it was thermal limiting a bit during the heat wave).

Should be viable with enough airflow if your rig is set up for proper cooling of the GPUs.

 If you're in a dry area, might want to consider an evaporative cooler.

Mining is a low-bandwidth activity.
Otherwise riser rigs wouldn't WORK for mining on.

The GTX 1070 is a better choice for ETH than the 1080 is - the 1080 should be mining ZEC if you are going to mine one of the "big coins" on it.

 I personally prefer Sapphire then Gigabyte then EVGA then MSI then the rest, but other folks have other opinions.
 
 X-1050 should be a good choice for your rig as designed.
 Just don't go with the Prime series instead, they're the first Seasonic series I refuse to buy in a VERY VERY long time of preference for Seasonic power supplies.
 

 Most modern GPUs *IF THEY HAVE A GOOD FAN SETUP* (insist on double ball-bearing fans, nothing else lasts as long in heavy duty usage) will last many years, if you keep the fan curve turned up enough to keep the card cool.
 I've got some cards that have been mining (or working the Dnet client which puts a very similar load on them, as it is ALSO crypto work) for 5+ years without issues.

 The biggest reason I prefer Sapphire is they don't make cards with anything else and haven't for as long as I've been aware of them.
 Gigabyte EVGA and MSI seem to be the same way but I have less experience with their cards.


 I mined part-time for about 5 years before I "went pro" last year - and had built up a significant "farm" in that time, largely from reinvesting a large part of my mining income.
 Then I moved to where the CHEAP power lives so I could afford to "go pro" a lot easier.

One thing to keep in mind about Skein.

 *ALL* of the Skein coins are very small market cap and very small "network hashrate".

 The profitability is jumping all over on those - even from one block to the next block can see a change of more than 30% sometimes.



 ZEC on the other hand has been climbing to the point it's usually competative - seems like quite a few folks with 1070s and a LOT of the AMD hashrate has been shifting to ETH because that is MORE profitable than ZEC at this time for the 1070 (slightly higher gross income AND lower electric usage) and most AMD setups.

 This will probably change over the next couple days of course, as folks see the shifts and bounce back the other way some.



 I've not been impressed with zpool.ca in any of my testing on it - the pool-side hashrate is always quite a bit lower for a given algo than I see on most other pools with the SAME rig over a 24 hour period, and the resulting payout is always noticeably lower than even the pool-side hashrate calculation should be giving - and that's BEFORE factoring in that ALL of the algos I have tried out there are MERGE MINING on at least one coin, which should be kicking the actual payout UP a hair from the calculated ones.

 They *do* seem to pay out better than Nicehash *SOMETIMES*, but only when a particular algo that Nicehash doesn't support has a particular coin that has had a major profitability jump and hasn't gotten jumped on yet by lots of miners.

RX 4xx is out of production, and the small remaining stock is generally getting crazy gouge pricing.
RX 5xx is not getting ramped up enough to support the demand, leading to gouge pricing as well.



 IMO if you're going to use Afterburner at all, set your cards with a fan profile not just a fixed fan.
 I usually use a more-or-less straight line from 30% at around 40C to 100% at 75 or 80 C (depending on the specific card model).

 That saves fan wear and tear when you don't NEED the extra cooling, but the cooling is THERE when you do need it.


 At CURRENT pricing on RX 470/480/570/580, NVidia is killing AMD pretty much across the board - it's pretty sad when major retailers like NewEgg are often charging MORE for a RX 470/480/570/580 than for some GTX 1080 models and quite a bit MORE than for most GTX 1070 models - when they have AMD RX cards to sell at ALL better than the 460/560.

Ignore X11 - ASIC mined for about a year now.

skein, groetsl, lyra2v2, are all good options for the 1070.

 Right now, ETH is earning more than ZEC on a 1070 but it's VERY close - and neither is the best option but they're in the ballpark with the recent price rises and the extreme shortage of AMD cards for the big boys to add to their big farms.

 The primary skein coins I am know about are DGB-skein and Myriad-skein (both of those are multi-algorythm coins, however).



 I've got a couple 1080s, but one just showed up and isn't in a system yet - the other I did some testing on, more or less a tossup on a hash/$ basis on ZEC mining and on skein - but it's doing "something else" not specifically mining related at this point where it's also a tossup with the 1070 on performance/$.

 Did you miss the "2x" part?

Right now, unless you can find them from someone that is NOT gouging on the price due to limited availability, it's a case of "buy what you can find" on the RX 470/480/570/580.

 RX 4xx series apparently has been out of production for a month or so, but AMD hasn't gotten RX 5xx production up enough on the 570/580 to meet the demand....

I didn't have power to run the last rig I bought parts for - when I bought it.

 But I knew I was moving into a new place with more power (took possession tonight), so even thought the parts showed up a day early I'm now SAVED!

 8-O

I keep forgetting Toomim are around here - somewhere - more or less close.

 (I know where they are at, and might even "drop in" on them next time I'm in their area, if it's during "business" hours, just to say "hi" and ask if I can get a tour).

The HD 6990 is Terascale, most recent miners expect GCN and either don't work with Terascale cards at all or not very well.

 Since you don't have any RX series cards listed, though, install the 15.12 drivers and try it - worst case the card just won't mine.

 The only power supplies I have ever seen that offered higher capacity when powered from 220 instead of 110 were SERVER SPECIFIC models.

 

 (To Phil)

 Try adding a Delta 38mm to the front of the case, fans that come with cases are usually seriously wimpy.

 (To Vosk)

 I would also not try 3 x 1080 ti in a non-riser build, the only motherboards that will let them space out properly to cool are WAY too bloody expen$ive and uncommon (the old Gigabyte -UD7 motherboards would work but ALL of them have been out of production for years and Gigabyte doesn't seem to be doing them on current chipsets).
 As a nearly-universal rule boards with 3 x 16-bit PCI slots space the #2 and #3 slot too close together to let the #2 card cool if you have another full-length card in the #3 slot - which is why I love the Gigabyte "ITX" 1070 card (MSI makes a 1070 that size now too) - they leave 1 fan totally unobstructed, which has been enough to keep the middle card reasonably cool in my 3-card no-riser rigs when the small amount of airflow the other fans get is added in.

 Some boards I've seen with 5 x 16bit slots OR MORE allow the right spacing - but BLOODY HECK you pay more for some of those motherboards ALONE than some of my 2+ card complete RIGS have cost me.


 Backplates on non-riser mining rigs are a BAD THING - they obstruct airflow.
 On riser rigs they don't matter, you just space the cards out more.

FX 8570 (octocore but the old Bulldozer-based) running JMiner (if I'm not doing anything else with the CPU) can almost keep up with raw hard drive speed of any non-SSD drive I have (I don't waste SSDs on BURST, but my gaming rig has one).

 Blago is a lot slower, 4x or thereabouts (FX doesn't support AVX2 he added support for in the newest version though).

 I've been toying with building a Backblaze "pod", but I'd probably beef up the recommended PS enough to run 1 or 2 of my RX 470s in it, or possibly 1 or 2 of my older R9 280x cards....

For the 7950, you might be better off going with UBuntu 14.04 and using the fglrx 15.12 (they are in one of the Ubunty repositories with "-302" as part of the name) drivers.

 I'm not sure if the "PRO" stuff supports older cards, though in theory it SHOULD work with anything GCN.


 Muddybit - it's called "lots of folks building new rigs adding to the hashrate raising the difficulty because of the crazy-high ZEC price rise the last 2 months or so" - so yes, you're right. 9-)

Most mining software is built to support GCN cards.

 The 6950 is Terrascale.

 There is at least one XMR miner around for 32-bit systems that should work on it (I have it running on an XP-based system with a GTX 750 ti but I think it's OpenCL based not CUDA specific, or it has an option for OpenCL), and I have had Claymore's ZEC miner running on an A10-5700 on the GPU (VERY slowly, but that's also a Terrascale GPU and I suspect it was handicapped badly by using system ram).

 Also, almost ALL mining software is built to use a 64-bit OS - your options are VERY VERY limited if you're not running a 64-bit LINUX distribution *or* Win7/Win10 in a 64-bit version.

 As a general rule, explicit SLI support by a motherboard isn't actually required to do SLI - that's more of a "yes, we tested it this way and certify the slots are positioned correctly to work" thing.
 On the other hand, SLI and Crossfire are going to be a dead issue in a few years, due to DirectX 12 support for asymmetric compute and multi-GPU support with no SLI or Crossfire needed.

 Your Xeon is serious overkill for a mining machine, mining doesn't need much CPU.

 Given the current pricing structure on the 1070/1080/1080ti they're all pretty close to a tossup as far as hash/$ goes at the system-build level on most coins.
 In theory, with your specified system and PS you should be able to use *2* of them eventually.

 Just don't try to stick an Aorus model (or any of the "2.5 slot" models) in a slot that doesn't leave it at least 1 slot worth of fan clearance to the next card over.

I'm not using any of the Gigabyte 1080 ti models, but the one you linked appears to be the 1080 ti version of the pair of 1080 cards I DO have.

 Should be reliable, and fairly cool, for a non-Aorus non-watercooled 1080ti.

 All of the calculators are too optimistic - but I think it's the fault of how BURST and it's pools are structured more than anything, the pools appear to only report the size of the last machine that reported a deadline when someone (like me) has more than one machine mining to the same address.

 I generally figure 30% less than what the pools estimate.