Topic: Potential Mining Rig Critique (Read 2052 times)

You are right. I misread "50-70% of the advertised PSU wattage" for  "50-70% of the advertised PSU efficiency". Sorry for that.  

Misunderstanding, we are talking about the same thing.  See my edit above.

True. Below 20% of the max. output the efficiency will be no good. But even the 1200W you linked has > 89% at > 400W. :-)

That 93% efficiency figure will be at a particular load, take a look at the efficiency graph for the beloved Corsair AX1200 (also 80+ gold) for an example:

http://www.corsair.com/ax1200.html

[edit] I see where I was unclear,  what I should have said is that the PSUs max efficiency will be at 50-70% of its maximum load, not that it would only be 50% efficient.  80+ means at least 80% efficient over all loads.

Modern PSUs should have a much higher efficiency. E.g. beQuiet say this about their 950W Dark Power:


Others are quite similar.

USB2 works great for most linux distros.  Most of the system will be running in RAM, not from the USB directly, so read/write speeds don't come into play often.  Especially for a dedicated miner.  Only thing to watch out for is if you plan on keeping log files; write them out to a network share instead of the USB drive.


Your 1000W PSU should handle them pretty well.  A really big OC on a 5830 might push 180W / card.  Not sure about your 6870's, but I can't imagine it's much more.  If you've got a kill-a-watt or something else to measure power at the wall, it's easy to see how much headroom you've got after the 6870's are in.

[edit] Just re-read and saw you're considering 2x 600 or 700W PSUs - this isn't a bad option at all, but I'd do a price comparison.  If you're going to have 4 cards eventually, and the power usage of those cards fits in <= 800W or so, I'd just go with a 1000W.  If it were 4 6990's on the other hand (350W+ each!) I'd go with multiple PSUs.  Remember your max efficiency is going to be around 50-70% of the advertised PSU wattage.


If this is going to be a dedicated miner, and you don't have the components already, I'd look at something with more PCIe slots.  3 * 16x slots is great, but you don't need that bandwidth for mining.  You'll find there are much cheaper options with 2 * 16x and 2 * 1x slots, which will work well with extenders.  More than 2 * 16x slots and you're entering 'extreme gamer territory' where prices climb quickly.

all you need is

- a piece of plywood
- a 900W PSU
- a mainboard with FOUR PCIE16 slots (doesnt matter if x16 x8 x4 x1)
- a sempron or something equally weak and cheap
- an old HDD, better even: win7 on a 16GB stick
- four PCIE riser cables
- four cards (i have four 6950s, wish i had gone for 5870s)
- some kids metal building toys (maybe playmobil and a dremel or some lego will work, too)


i did start out with a case, but learned the hard way that shit just gets TOO HOT TOO QUICK. 

care to look at my caseless rig:



from left to right:
HDD, PSU, Board with three cards (fourth about to be added)
That's it. Mainboard is screwed to the board.

The hardware would be installed before it gets THAT cold, probably once the temps are in the 50F, October-November.  We usually get our first snowfall in November, right around Black Friday. I can only hazzard a guess that if the system is operating to a good degree (pun) before the real cold hits that it can compensate.

I am definitely thinking that a linux distro would work better and installed on a bootable USB thumb drive, or maybe even a USB3 thumb drive due to the increase in speed.


The 6870s are cards I already own, so they are kind of the default to start with.  Would there be any problems with me added a 5830 as the third cards in the system?


Does anyone have an opinions on the board or the processor to be used?  Is 3 x16 slots and no x1 slots worth it?  It does have two non-e PCI slots, and I know there are adapters to convert those to x16, but i have yet to hear a consensus good or bad on those cards.

Not for long   You'll find out quickly that these rigs make excellent space heaters.  I plan to duct mine into my furnace this winter to warm the whole house.

6870 is overpriced for mining, +$50 USD over the 5830 which has the same number of shaders.

Go for the 5830, or go for the gusto and reach into the 6950/70/90 area.

You'll probably want to do some experimentation on case vs caseless; if you're going to have a harddrive or other moving components (other than fans, those should run fine), you should probably use a standard PC case. 

If you can boot from USB or the network instead, go caseless - with ambient temps like those you'll get some pretty nice wintertime overclocks

IIRC, temperatures below 0°C don't go to well with standard PC hardware. Some parts (like HDDs) probably don't like it at all.

You might want to use a standard midi case to actually keep the heat in!

That said, I am running two 5850s now on a 950W power supply and it is using ~400W from the wall socket. So I could probably run 4 cards of that PSU.

true, though i would like to have the ability to easily move the rig as a whole without having to move much of the individual components, and the open air frame sounds like a fun project overall.

Most people do not even use a case.

The money you spend on a case could be better spent on good shelves where you get place 1 or 2 rigs.

Instead of a 6870 go with the 5830s cheaper and more potential (plus they run super cool).
To give you an idea on power I am currently running 2 x 5830s stock voltage overclocked to 1000mhz
I think with one 1000 you should be more than OK.



Good luck!

So I have decided to make my Northern Michigan Winter rig that will be running in a room that is snow-proof, but not heated.

Before I start gathering the parts together, I want to get some opinions on the CPU and Motherboard choices.


I am looking at an "Intel BLKD975XBXLKR LGA 775 Intel 975X ATX Intel Motherboard"

The board has 3 PCIe x16 slots, and irregardless of their speeds, we all know they will mine just the same.

The CPU I would possibly use is a Celeron Dual Core.

The power supply would probably need to be 1000w so I have some room to add that third card.  Or would it be better to go with two lower watt power supplies that way a single wouldn't be taxed as much?  Two 600w's perhaps?  700?

The case will either be one of, or will be based on, Detritus's "Open Frame Mining Rigs" and as said before, stored in a room that IS snow-proof, but is not resistant by any stretch of the imagination to the temps outdoors.

The lows it gets around here from December to March can be around 0F to -18F (-18C to -28C), but the averages are usually 25F to 5F ( -4C to -15C ).  These would most likely be the ambient temps in the room the rig will be located in.

The rig will start with two VisionTek 6870s, adding another card and or swapping them out with better hardware soon after if the rig performs well (enough).  I plan to use the x16 extension cables.

I have extra copies of WindowsXP Pro, and am more comfortable with it than Linux.

There will be no hard line connecting the rig to my main network, so I will need to use Wifi.  Only way to run a hardline would be to dig up the parking lot and run the line, and we don't plan to do that for normal network extension until next spring.

I have a number of WiFi signals I can connect to (my personal/private networks, and an encrypted motel guest wifi for my customers).  I believe if I can get the rig to connect and remember all of the wifi networks, I should be able to reduce downtime due to signal loss.  I will work to get the antenna placed properly though, thats for damn sure.


What I do wonder is, in a cold environment like this, if I should adjust Detritus's open frame design to support the graphics cards with fans facing down, rather than on their side like in his case design, in order to pull in cold air better.  Then again, spacing out the cards just enough should help.