Building the Ghetto rig – part 3

So we had four cards up and running in the Ghetto rig. We were short a PSU with sufficient PCI-E ports to connect the final two, but recently we got a hold of the cables that made it possible to switch out a Corsair HX1050 from one of our gaming rigs. Then we could connect the last two cards and it eased our worries that a 750W PSU couldn’t handle the stress very well.

new psu

new Corsair hx1050 PSU

new psu in place

new HX1050 PSU in place

We also got two more case fans to drive out the heat from between the two new cards as we did with the ones that were already mounted.

6 cards mounted

6×1060 mounted on board with new case fans

Easy peasy, six cards up and running. When mining with all six 1060s we only use 591 W from the wall!

drawing 591W

Using 591 W of power from the wall while mining with 6×1060

..and we are hitting 130 MH/s, maxing out at 60 C per card.

mining with 6x1060

Mining with 6×1060 using Claymore and reaching 130 MH/s

Since the cards where not standing up by them selves very well we screwed each card to the board.

stabilized gpus

GPUs stabilized by extra screw

And that’s it! The rig is complete. It’s quite portable, somewhat modular, less power consuming than we initially thought and now it remains to be seen if it’s profitable. We are aware that we started this project late into the mining craze and right now profitability mainly depends on the future price of ETH. I hope to follow up with a post on the economics once we have enough real life data on power costs and ether yield.

Tuning the ASUS 1060 DUAL 6GB GPU for Ether mining

When mining for ETH you really want to get the most hashes per second at the lowest power consumption possible. There are a couple of calculators out there to help you play around with these parameters and see what kind of profit you would be getting.

I bought a power meter and plugged it in to see how much power my rig was consuming when mining. I also installed ASUS GPU Tweak II to be able to control some parameters of the ASUS 1060 DUAL 6GB GPU and HWInfo to get more detailed reading on memory frequencies, temperatures and power consumption. This was from running on stock settings:

mining on 1060 DUAL 6GB on stock settings

mining on 1060 DUAL 6GB on stock settings

consuming ~138w when mining on stock settings

consuming ~138W when mining on stock settings

I was getting out ~19 MH/s from the card and reaching temperatures of around 66C. The machine consumed about 138W and the GPU was using 100W.

It turns out, these stock settings are not optimal for mining as described in this article. You can lower the power target of the GPU and boost the memory clock significantly to get higher hash rates at lower temperatures and lower power consumption! Almost sounds to good to be true, but have a look:

mining on 1060 DUAL 6GB on modified settings

mining on 1060 DUAL 6GB on modified settings

consuming ~119w when mining on modified settings

consuming ~119W when mining on modified settings

I was now mining at ~22MH/s at 60C and only consuming 119W instead of 138W and the GPU only drawing 82W. The conclusion is that tuning matters, a lot! Numbers add up quickly when you have a mining rig running 24/7.

I played around a bit with the parameters of GPU Tweak II and found that the memory clock is the one that counts when it comes to hashrate. Underclocking it by 1500 Mhz got me a hashrate of ~12,2MH/s and overclocking it by 1500 MHz got me to 22 MH/s. The power target parameter mainly affected the power consumption, although bringing it down to 50% killed the hashrate as well. Setting the power target at 70% got me the best hashrate per Watt ratio. The GPU Voltage and GPU Boost Clock parameters didn’t do much for the hashrate at all.

Also, it looks like I’m not really utilizing my 750W gold rated PSU. I might try sticking in one more 1060 GPU in there. I wont be able to run the cards in SLI so it won’t improve gaming performance, but it would double the hash rate when mining.

What a difference a GPU makes

Putting things together

CPU mining wasn’t getting me anywhere as I wrote so I went shopping. Worst case was that I would be losing interest in mining and end up with a perfectly good gaming PC so win-win! This build isn’t at all optimized for mining but it did help as a proof of concept, and it does run Battlefront on Ultra settings in full hd at 60 fps. Here is what I went with:

  • ASUS Prime Z270-P motherboard
  • Intel Core i5-7600K
  • ASUS GeForce GTX 1060 6GB DUAL GPU
  • Corsair PowerSupply (PSU) RM750x 750W
  • Corsair Vengeance LPX White 16GB (2x8GB) DDR4 / 2666Mhz / CL16
  • Fractal Design Define R5 – White / Window case
  • Samsung SSD 960 EVO 250GB
  • be quiet! Pure Rock CPU cooler

When building a mining rig you wont need that much RAM or a powerful CPU. Just lots of GPUs, some means to connect them all to your motherboard, a special case and a really powerful PSU. My build, as I said, is more of a mid range gaming PC that happens to do some mining.

components for gaming/mining pc

result of shopping spree

I hadn’t put together a PC from scratch for at least 15 years so this was good practice for me. It took a couple of hours, I struggled some with that CPU cooler, but in the end it worked out great.

Putting things together. Yes, I know that cooler is upside down. No, I wont fix it.

Payoff

I had been getting about 80 kH/s mining Ether on my Azure Ubuntu VM. Now was the time to see what that 1060 GPU could do. Turns out, a lot better. ~19 MH/s. And the thing wasn’t even running that hot (66C) and almost completely silent inside that Fractal case. The first payouts from Nanopool were coming in after a couple of days and my Ethereum wallet were no longer showing 0.00 ETH in balance.

Next up, tuning it.

gpu mining

mining eth on stock settings with 1060 DUAL 6GB

1060 in case

a look through the window of the fractal case

And more fans!

It wasn’t at all necessary for this build, but I got two more case fans some days later just because I could. One pushing in cold air from the bottom and one pulling out hot air at the top. This meant taking out some parts of the Fractal case and that was easier said than done. End result:

gaming-mining rig

Everything put together with two extra case fans