Solution: How to run 2 PSUs on one motherboard!

If you want to build a Bitcoin/Litecoin/Altcoin mining rig (or a real heavy game computer), you might consider to buy 2 PSUs instead of one very expensive. In this case, you have the problem, that the second PSU is not connected to the motherboard and will not start, when you turn on your computer.


I am not aPC expert. If you try this, you might break your PC or components. You will lose all your guarantee. When you read this, you should NEVER try this on your own machine/components!

Solution 1:

Shortcut the green cable with the black cable (see picture). As your PSU might have different cables and/or colors, you should check this very carefully, here’s a good description link:

Some ppl do this with a paper clip, others with a cable. Whatever you do, you need to make sure, it never slips out of the connectors.

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Solution 2:

Buy a special adapter:


If you want to see, how to build a mining rig with 5 or 6 graphic cards, check this article:

The top 10 tools for Twitter and social media

twitter-logoI write about the best Twitter tools on a weekly basis, as well as decribing the best work methods to increase your productivity (by decreasing your time needed to follow and post).


HootSuite – Website: – The best service these days, and for most uses, the free program is sufficient. Use it to colect different content streams and follow them easily (e.g. one for #bitcoin, one for #management and one for #fun). But you can also use it to post with one click in different social media. From my day-2-day experience, I strongly recommend to use Hootsuite ONLY for reading! To post your content, you should always take the time to do it manually in each social media directly. The additional time

Alternatives to Twitter:

Twister (Download at is pretty similar to Twitter. They key difference is, that it works without a centralized database or server architecture. This means: there is no database that holds all user’s information. Due to this, it’s pretty complex for hackers to get the individual’s data, but also legal authorities cannot easily shutdown the whole network (which they can doe easily, when a program or a website is the center of all activities, as it is the case with most tools like Twitter).Find detailed information at


How to build a Mining Rig with five graphic cards (AMD 7970/R9 280x)

Here I will blog about, how I build my first mining rig ever. This mining rig is not for BitCoin mining (you use ASIC chips for this), instead I want to use this rig for mining so called „AltCoins“. For example LiteCoins (LTC), PeerCoins (PPC), DOGE (DogeCoins) etc.

This mining rig will work with five(!) or even six AMD R9 280x cards. This blog covers not only the hardware, but also explains, why I chose these parts and the resources how I got the information for this.

If you have questions or want to leave a comment:

My key learnings in this project

  • I learned how to start a computer with a screwdriver (feeling bad ass now!)
  • The BTC/Altcoin communities are awesome, feels like the 80s. People are willing to help, because they love to. No-one is called a „noob“, no trolling. Really a big difference to regular discussions in the internet today.
  • When you buy 3x the same graphic card, you will get 3 identical devices, but each will perform different. I experience about 9% difference between the graphic cards.

Hardware list

So here’s the hardware for this mining rig:

PSU and power consumption

  1. First of all, you need to be aware, that graphic cards consume significant more power when mining, than when running a game. If you plan your own hardware, use this sheet as a reference:,Marque_fbrandx32,2981.html
  2. In my case, I want to run 5 cards of type R9 280x, so they will need 275 Watts each, a total of 1350 Watts.
  3. On top of this, you need to calculate 100-150 Watts for the other hardware (mainboard, HDD, fans etc).
  4. This means, the PSU needs to have an OUTPUT of 1500 Watts. But you should never run PSUs on 100% load for 24/7, so in this case I need to have a minimum of 1700 Watts output.

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There are only very few PSUs available, that have an output of more than 1000 Watts, and even less can give you 1500+ Watts. So instead I buy two PSUs with 850 Watts each. A lot cheaper this way. But this means, the PSUs need to be connected in a special way (green cable needs to be connected), I will describe this with details and photos later. Until then, here’s a video: and

If you run 2 PSUs instead of one big one, you need to shortcut it or get a special adapter. Details can be found here:

Sometimes people start to talk about the 12V rails. Here’s a great article about it: – plus a nice statement:

Graphic cards

DSC01955 800x422Below you find the most recommended AMD cards for AltCoin mining.Details about their hashing power, plus, more important, the settings to achieve these results, can be found here: . When you want to buy a card, make sure that the chip on the card is exactly the same, as listed in the Wiki, otherwise you might get completely different results.

7950 (old card, very hard to get).

7970 (most people recommend this card, because it needs less energy than the other cards (215 Watts, while bigger cards need .270-315 Watts). In most shops, this card is out of stock, this is why you should consider he following card:

SAPPHIRE R9 280X 3GB GDDR5 – if you can’t get a 7970 card, then use this one. It costs about the same price, has a little more hashing power but needs somewhat more power (270 Watts). (Links: |

R9 290x – if you don’t need to pay electricity bills (lucky you), then you can go for this card: very high energy costs, but it can be run with 950 to 1000 kHash.

Operating System + Drivers

I run the machine under Windows 8.1 currently. For this I need the OpenCL.DLL , this means you need to install the AMD ADL SDK 6.0 from .

Got errors? Here’s some help!

Whenever I run into a problem, I will log it here…

  • Your rig/mining machine does not start at all?
    • it’s likely that your PSU does not has enough power reserves. Disconnect a few card and retry.
  • Graphic cards are not registered?
    • Possible solution 1) you need to connect both power cables (8 pins AND 6 pins)
    • Possible solution 2) your riser cable is not working, just try a different one
  • Your mining software claims „OpenCL.dll missing„?


Mining software

  • When using AMD (ex-ATI) cards, you need to mine with cgminer or sgminer (link to come). I recommend SGminer, as cgminer for altocins is not supported anymore. If you want to run cgminer, be sure to use version 3.7.2, newer versions of cgminer will not work with altcoins.
  • When running  NVIDIA cards, you should use cudaminer (link to come).
  • When running Windows, you can use CGWatcher (link to come), perfect to play around with the performance of your cards, also more details than just the mining software.  Very easy to laern and very handy tool.

What happens right now?

12.02.2014:  My hardware arrived today *happy*. two 280x cards are missing, but it’s a start.

DSC01872 1280


15.02.2014: assembled everything, but just with one card as a test. All runs fine on Windows 8.

16.02.2014: assembled the rig with 2 cards in a plastic crate. Runs fine, but gets hotter than expected. So not running it 24/7, will build a bigger and more open rig first (wood or aluminium, not decided yet).

18.02.2014: with some help from Multipool’s IRC channel, I was able to optimize my card’s settings. Still running with 2 cards only. Strange: card 1 runs with 707 kH/s, 82 degrees, fan at 3300 rpm, while card 2 runs on 725 kH/s, 77 degrees at 2700 rpm. Big difference for similar cards (same product, same chipset, same BIOS). Can’t wait to check card #3, but can’t do that until Friday.

11.03.2014: had big issues with the riser cables: 4 of the 5 were broken. Took quite some time to get new ones from a different merchant. Currently the rig runs with 2x Sapphire R280x Dual and 1x Sapphire 280x TOXIC. Rig currently runs on 2 PSUs, total of 0,999kWh. Heat: The GPUs are all around 76 to 78 degrees (celcius), Fixed voltage. See picture:

DSC01955 800x422



Some of the resources I learned from during this small project: