Litecoin build for noobs: 3x 7950s (1.8 MH/s) in a $10 crate case

[MKEGuy]

I've found that for the 7 series (7970s myself), powered risers are completely not necessary.  I have two cards running 16x to 16x and two running 16x to 1x.  No jumper wire, no power, nothin.  Actually, technically 1 rig has 4 cards and 1 rig has 3 cards for now.  Ordering another 7970 very soon.  But funny enough the rig with 4 cards is the more stable rig for some reason.  I'm curious if that will change when I add another card to "balance" things out.  Though technically it shouldn't make a difference, experience has definitely taught me otherwise!

Nice little guide to get people pointed in the right direction.  A lot better then some of the advice I've seen floating around out there!!!!

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[Joerii]

.... But funny enough the rig with 4 cards is the more stable rig for some reason.  I'm curious if that will change when I add another card to "balance" things out.  Though technically it shouldn't make a difference, experience has definitely taught me otherwise!.....

Be careful MKEGuy ! I'm sure there's a good reason why it's not viable for a long term solution. Can the motherboard keep powering 4 cards like that without, eventually, burning out somewhere ?

Taco we need your wisdom

[Joerii]

Has anyone tried this built yet ? I ordered all the parts. I have to look around for a nice crate though, we don't have Home Depot here in The Netherlands.

When I start building I'll post some pics.

[tacotime]

.... But funny enough the rig with 4 cards is the more stable rig for some reason.  I'm curious if that will change when I add another card to "balance" things out.  Though technically it shouldn't make a difference, experience has definitely taught me otherwise!.....

Be careful MKEGuy ! I'm sure there's a good reason why it's not viable for a long term solution. Can the motherboard keep powering 4 cards like that without, eventually, burning out somewhere ?

Taco we need your wisdom

All I know is that my 3x 7950 rig has mined for 6 months without issue.  I think it's less than ideal to pull (80w * 4 = 320w) from that motherboard, but that's just me.  If you want to put more cards on the board, just add powered extenders.  But be aware the the motherboards have high resale value anyway, and you need to buy progressively more expensive PSUs to power them.

[tacotime]

Thanks for that noob built. I'm going to try it out ASAP.

Two questions :

1 How about airflow for the mobo ? I've read that there's parts on it that need some airflow to keep them from overheating.

2 Could you elaborate a bit on why using a powered riser is so much hassle ?


I did some math and all the parts for the machine , except for the GPU's,  cost €366.  If you add another GPU you would divide that cost by 4 instead of 3, €91 instead of €122 per GPU. I guess this is not a big enough number to risk frying a rig over though

And I also did not take into account how much more a more powerfull PSU costs. But you could use the same Mobo if you use 4 7950's, right ?

1. I'm not sure where this comes from, but it's really not an issue on any of my rigs so far (maybe if it gets hot enough, it will be).  Pull out an infrared heat gun and hit the caps with it, all mine are at under 30C.
2. Just because of getting enough molex cables from the PSU and the A1-B17 shorting issues.  Right now I have one rig with 4x 6950s and powered risers and it's like a jungle beneath the cards.

And yeah, if you want to power 4x 7950s you can, but I would just make another rig at that point.

[shinkicker]

Just quick question if I may.

Once you have everything connected. which port do you use to reach the bios? Is it the main PCI-E slot with a hdmi or do you use the VGA socket on board?

[tacotime]

Just quick question if I may.

Once you have everything connected. which port do you use to reach the bios? Is it the main PCI-E slot with a hdmi or do you use the VGA socket on board?

Use HDMI or DVI from any card in a PCI-e slot

You may have to melt a hole in the side too to get USB peripherals in like keyboards or Wifi adapters (just use a cheap $5 soldering iron)

[hiima]

Gonna have to try this out for LTC mining.

[Joerii]

I think i'm just going to get a slightly bigger crate instead of messing around with molten plastic hahah

[nanobit]

Awesome post, Taco, thank you!
One question though, which I'm sure other readers are wondering too: is it still worth investing ~1200 euros on LTC mining rig at this point in time? What are your thoughts on ROI? I'm sure you thought about that while writing the guide.

[Joerii]

About to assemble my first rig. I'll call it the TacoMiner, as a tribute.

Last question : can I use a flash drive instead of the SATA HD ? I want to start with a windows system first though, I need to study up before I can use the linux command line interface.

[kokojie]

About to assemble my first rig. I'll call it the TacoMiner, as a tribute.

Last question : can I use a flash drive instead of the SATA HD ? I want to start with a windows system first though, I need to study up before I can use the linux command line interface.

No, you can't use a flash drive for installing windows. You can only do that with linux.

[tacotime]

About to assemble my first rig. I'll call it the TacoMiner, as a tribute.

Last question : can I use a flash drive instead of the SATA HD ? I want to start with a windows system first though, I need to study up before I can use the linux command line interface.

As far as I know, no, not with Windows 7 at least.  I always use SATA HDDs.

[nanobit]

Taco, do you have any guestimates on what's the ROI for a rig like this, or is that a question to another discussion thread? 

[bitcoinnix]

Taco, do you have any guestimates on what's the ROI for a rig like this, or is that a question to another discussion thread? 

Longer by the minute with difficulty skyrocketing.  All the bitcoin miners are swarming us.

[MKEGuy]

.... But funny enough the rig with 4 cards is the more stable rig for some reason.  I'm curious if that will change when I add another card to "balance" things out.  Though technically it shouldn't make a difference, experience has definitely taught me otherwise!.....

Be careful MKEGuy ! I'm sure there's a good reason why it's not viable for a long term solution. Can the motherboard keep powering 4 cards like that without, eventually, burning out somewhere ?

Taco we need your wisdom

Considering how far the cards are undervolted and the power they are consuming.  The PCIe cables are capable of supplying almost all of the voltage. Feeling the extender cables there isn't even any warmth to them which means there isn't a lot of power being pushed through them.

If you are running them overvolted and such - then as a precautionary measure, by all means run powered risers.  But if a problem were going to creep up. It would have done so already.

Taco is an awesome source of information, and I"m glad you newbs have some direction to follow - but trust me when I say no one is the end all, be all of information in this segment.

[tacotime]

The problem isn't the power going through the extenders, but rather through the 12v connection on the 24+4 pin cable: https://bitcointalk.org/index.php?topic=102890.0

[tacotime]

Taco, do you have any guestimates on what's the ROI for a rig like this, or is that a question to another discussion thread? 

It took me about 3-4 months to pay off mine 6 months ago, I would suspect with the rising difficulty it will be similar.

[nostradamus]

Why the 8 GB of ram?  I thought LTC mining used the onboard GPU ram...

[tacotime]

Why the 8 GB of ram?  I thought LTC mining used the onboard GPU ram...

You need the equivalent amount of RAM used on the cards on the system -- it's an opencl bug