Bitcoin Forum

Hello all !

I'm Zemou from France. Starting mining alt currencies. I've been lurking this forum for a while and decided to do my first post :)

Here a picture of my mining rig with 3x HD7950 and 1100 watts PSU and made of wood (around 4 hours of wood work...) :
http://img11.hostingpics.net/pics/984067photo.jpg
EDIT : The picture is from the top of the mining rig. Card are in vertical configuration. I'm planning to add 3x 140mm cooling fan at the bottom of the case to bring the fresh air.

Each card is currently mining Litecoin at 640 Mhash/sec with the following O/C : 1070 Mhz / 1650 Mhz @ 1,10, all fans at 100% and each card is around 70°C.

As you notice on picture, there is also a HD6950 waiting to mine.
If I plug it, Windows doesn't start at all. In fact, Windows will don't boot at all if I use more than 3 graphic cards (whatever combination between HD6950 and HD7950).
Does anybody have an idea about what happens ?

Another question, does my HD7950 configuration/OC looks good for 24/7 mining ?

Thanks !

I'd bet the 4th card won't work because you are putting too much of a load on the PCI-e bus voltage. Are you using powered riser cards? It doesn't really look like it. I'd try using one or two and see if windows boots then.

Have you calculated your electricity costs over profit? I wonder how much electricity costs per Kwh there in France. Anyway Bonjour Mon Ami.  ;D

Indeed, I don't use powered risers.
I've to find where I can buy some of them...

For electricity, I pay 0,08 € / Kwatt hour. Following my calculation, it should be profitable :) (Something like 50% of revenue for electricity and 50% in my pocket).
But I've already ordered a kill o watt to be check my estimated electricity consumption...

You might be able to modify the ones you have, or at least that one extra. I believe I've seen a thread on the subject around here before. If you are good with soldering I'd give it a try.

Good luck mining.

Yes, I've seen this topic about homemade powered risers. I will make a try.

BTW, other people told me I need a dummy plug on this card. What do you think about that ?
(I'm using Windows 7 with Catalyst 12.8)

hi, nice rig! looks very good, i'm jealous.

Thanks :)
Made with 10 € of wood, some glue and nails.
I'm already thinking of making a new one as this one haven't enough space for the PSU.

A dummy plug won't keep windows from starting, it'll just keep the card from showing up in CGminer when you go to use it. I used single 75ohm (I think) resistor just shoved into the DVI plug on the card for a time.

I think I've found my final O/C but I'm a bit surprised with my values :
1050 cpu / 1500 memclock @ 1.000
Sucking about 350 Watts at wall plug (I've got a 1100W PSU with silver certification).
I was thinking about adding a fourth HD7950 but I will already reach the limit with these three...

Is it a normal watt value for a HD7950 ?

Should I underclock to be able to put the fourth card ?

Yeah underclocking would be better in the long run because additional rig would make you lose on electricity due to extra consumption (Hard Drive, Ram, Processor, Board, etc.). Also you could crank down your mining software settings to minimize consumption.

I'll watch for underclock/undervolt...

Another question :
One of my HD7950 keep crashing everytime I start mining with it (ATI display driver crashes and Windows recover it). I was overclocking it...
Now even at stock frenquency, it still crashes...
Nevertheless, it seems to work good while the computer is idle. I also can plug the HDMI into it and the image is good on my screen.

Any suggestion about this ?

Wood?  Is that dangerous?  Flammable? :P

Ahah! I will put some special paint against fire on it :)

By the way I solved all my issues.

Is it a good performance to hash at 1900 MHs/s for a total consumption of 750 Watts ?

Nice!

C'est du beau travail  ;)

Wood are bad thermal conductor. And it is flamable.. It beter to use aluminium. Its cheap and easy to cut.

I know a wood frame can be a bit risky but will not burn with 70°C... By the way, the system is in the basement of my place which is fully made of stone :p

BTW, I solved all my problems (stability, windows doing shit, card not recognized) by throwing away GUIminer and using CGminer instead.
Moreover, I have some room to undervolt a bit more ! I decided to stay at 1050 / 1500 mhz as it provides satisfying hash rates (around 630 Kh/s per card for a good).

Right now, two cards are "optimized"
@ 1.024 V
@ 1.012 V
The last one is still "in progress" but I will don't reach so good voltage as the ASIC quality shown in GPU-Z is very bad (66%).

I already disconnected all useless stuff on the motherboard but I still have to underclock/undervolt the CPU and the RAM (Is someone has a good guide to do this ?)

More pictures soon, I've added a space for PSU on my wooden case and managed all cables to make it "portable".

Yes, I hashed with 5850 somewere 350MH and 400W total. But the difficulty I stopped was 4M  :D

Hmm I don't think so. You can get 1900MH/s with ~ 6 Block Erupters each consuming 2.5W totaling in 15W.
This would be the same hashing power at 1/50 of the energy cost.

You must know something I don't, mining litecoin with those  ::)

Final clocks :
1050 / 1500 @ 1.012 V (77% ASIC quality)
1050 / 1500 @ 1.024 V (75% ASIC quality)
1050 / 1500 @ 1.056 V (66% ASIC quality)

Temp : all cards at 70°C with fans around 60-70%.
Total hash : 1900 Kh/s
Total consumption : 750/800 watts

I could overclock cards a bit more but I want to preserve my PSU.

I will add the fourth card as soon as I'm done with CPU undervolting.

Any guide for underclocking/undervolting CPU ?

EDIT :
After 24h test, the card at 1.012 V will be finally at 1.032 V which seems to be it's stable limit.

Oh, sorry I overread the litecoin part *blush*

Finally I think I'm going to get a fully stable rig (one week to solve various issues...).

Nevertheless, I still have this Sapphire Trixx issue. It doesn't want to keep my voltage when I reboot my system (clocks are back but not the voltage which seems to reset at stock value). Any idea ?

What motherboard are you using for your setup?

Welcome, and happy mining!  :)

Gigabyte 970A-DS3 (rev 3.0) with up to date BIOS.

Looking good that equipment , but if you just started the job why havent you start with ASIC USB Block Erupter ? it would have been cheaper and easier

That's exactly the way I thought about this "mining adventure".

Started to read about mining bitcoins something like 3 weeks ago. I also looked at these topic for group buy chips and PCB. But it looked quite risky regarding the difficulty rising up and not guaranted shipping delay. And more risky as these buying groups are often from USA or AUS.
Then I rade about Litecoin and other alt-currencies. I liked that mining scrypt was GPU-based and ASIC-proof (for the moment...).
If mining do not satisfy me, I will sell one HD7950 and PSY, buy a better CPU and smaller PSU and it will be a gaming rig!

I bought some second hand stuff :
- MB: Gigabyte 970A-DS3
- PSU: UCP 1100 watts 80+
- GPU: HIS 6950 IceQ X
- Few more stuff like screws, risers and RAM.
I regret for the HIS GPU as I immediately bought brand new 3x HD7950 (I'm currently selling it on Ebay but it seems I will loose around 40€ on it :/ ).

The whole rig cost me 800€ (around 1000$).
And soon more 190€ for the last HD7950.

Following my calculation, I can easily sell all my current stuff for 500€. So the risks are quite small.

I'm also thinking about buying some USB Erupters but it will be only on second hand market and to fill my USB ports. :D

I've got a question for you all :

What software are you using to remote your computer ?

I've been using Teamviewer which is really simple to use but I've noticed it makes my ATI driver crash randomly when I connect to my miner.

I still use teamviewer, logmein doesn't work at all...

But there are times when teamviewer crashes the drivers, next time I load up teamviewer I get a blank screen. Only the area around my mouse cursor refreshes, so I end up with a bunch of boxes all across the screen.

I fix it remotely, though at first even if you restart the PC it will continue going back to the blank screen. The only way to get it back is hooking the rig up to a real monitor after restarting, or in my case a dummy plug. Then, when it restarts it thinks it's hooked to a real monitor which I guess reloads the driver. Teamviewer works then, at least enough to run "headless."

It's not too often I have to deal with that, so I haven't worried too much. Hope that helps you out a bit.

Thank you for you reply ! I'll stay on Teamviewer then.

New problem and I think my PSU is dead...
I added the fourth HD7950 two days ago. It was taking 1050 Watts from wall. This morning, the rig shuts down.
Now, I can't mine. As soon as I start CGminer and GPUs, it shuts down.
Is my PSU broken ?

My PSU is a Coolermaster UCP 1100 Watts.

Remove a GPU and see if it will mine. I had a rosewill 1300W at first that mined fine for weeks, then all the sudden it would restart as soon as you started mining. Three would work though so I figured I pushed it too close on the wattage. A new EVGA power supply has been running it since. 4 7970s, and I pull right around 1400-1500W from the wall.


Enough to dim the lights pretty good  ;D

Joli!
I wish I had a mining rig aswell :(
Maybe youre overloading the PC somehow?

I forgot to say that it happens even with 1, 2 or 3 cards plugged.
Sometimes it mines for few seconds and then shuts down.
If I don't mine, the computer never shut down.

EDIT :
I found out : I burnt the ATX connector on the MB...
http://img4.hostingpics.net/pics/705988IMG2844.jpg
The burnt pins are both +12V connectors

I think the PSU is ok (hopefully).
I wonder if I need to change my MB or I can just clean it and add powered risers, any idea ?
Otherwise I will buy a new one with power connectors for PCIe.

Anyway, cleaning PSU pins is going to be a pain in the ass...

EDIT 2 :
Cleaned ATX pins a bit and connected only 2x HD7950 and looks good.
I'll try back to connect 3x HD7950 and I will wait for my powered risers for the last HD7950 :D

EDIT 3 :
The area on the ATX connector is still very hot. Going to wait for powered risers before doing anything...

EDIT 4 :
Going to put 2x powered riser and keep 2x on non-powered riser. Not enough molex on the PSU and 2x GPU should be able to get power through MB after a good cleaning.
Also building a compact aluminium case...

Finally, two cards was still too much on burnt pins, it still get really hot.

So, I made custom made powered risers following this guide :
https://bitcointalk.org/index.php?topic=76121.0
Two of them are connected on Molex connectors and two others on P4 connectors on a free rail of PSU

Now, it mines like a charm, even if the MB is burnt :D

I think I should write a big troubleshooting guide as I think I encountered all the shit a miner can encounter...

You were mining on 4 unpowered risers on a board not specifically designed for quadfire?

I could have told you that would happen!! Too much current for the little mobo pins to handle. Most boards made for quad SLI/fire use an external molex or sata connector.

http://i879.photobucket.com/albums/ab357/pontiacg5_2010/IMG_20130925_150726_zpsfb1ccdc9.jpg?t=1380139737

Hash long and prosper! :)

Thank you :)

And yes, I'm using a shitting MB which cost around 50€ only made for dual GPU configuration.
I also redistributed GPU around x1 and x16 PCIe connectors as I couldn't use 3 PCIe x1.

And I encountered another problem :
http://img11.hostingpics.net/pics/810920MiningPB2.png

One card is mining below the others (same O/C). It happened to me once but the issue solved itself. Any idea ?

EDIT :
Ah! Pontiacg5, I think I solved the Teamviewer issue (making the ATI driver crash randomly). I just removed the background image used by Windows and put a block color instead. Time will tell if it is really the solution.