Building the Ghetto rig – part 2

After waiting for weeks for the Chinese to deliver some sort of sign that they were planning to ship the PCI-E risers I ordered, we tried Amazon instead and had them delivered after a couple of days. That meant that we were ready for the second part of building the Ghetto rig. But first a look at recent events…

The last couple of weeks has been interesting

crypto right now

crypto right now

eth usd 60d chart

eth usd 60d chart

Whats behind the plunge in the graph? Lots of things. ETH was up over 5 000% this year when it hit the all time high around $400 so part if this might be the market making a needed recovery. Early investors are bound to cash in sometime. Also, the ETH price follows its big brother currency Bitcoin closely and recent worries in the Bitcoin community about a possible split and protocol changes affected the whole crypto market. The price is up 33% today at the time of writing, so the next couple of days should be interesting, specially from a trading perspective.

Mounting the risers to the Ghetto miner

But we are not trading right now, we’re mining! We headed out to a hardware store to buy a normal wooden board with the dimensions 20 cm x 100 cm x 2 cm to have something to mount the risers on. We reasoned that wood is cheap, sturdy and easy to work with. It worked out well! I sawed it off to give each riser (and GPU) 10 cm. Pro tip: before screwing anything together, measure it out properly so the cables from the motherboard and PSU will reach the cards.

measuring out the cards

Measuring out the cards on the board

measuring out the risers

giving each riser and card about 10 cm each

We fastened each riser to the board with two screws, four seemed like overkill for the job. To mount this glorious looking GPU board to the mining “case” we drilled two 4 mm holes through the case and the board and screwed it together. This brought some much needed stability to the rig.

Risers installed

Riser cables going in to the motherboard. Get all your cables together before mounting something obscuring on top.

Risers screwed to the board

Risers screwed to the board and board screwed to the case

board to case

board screwed to case

Mounting the cards to the risers

Now we are getting close. Just put the GPUs in their risers and hook up power to the riser and the GPU. We got SATA power cables with the risers but after reading this post on Reddit we were not going to use them. The risers themselves had molex connectors so we just hooked them up directly to the PSU.

cards mounted

cards mounted and hooked up on the board

You might have noticed that we only mounted four of our six cards, and that’s because we haven’t solved the PSU situation yet. The Corsair RX750 we have right now only supports 4 PCI-E cards and it would probably not handle the power load from six cards very well either. But four out of six ain’t half bad and it will be easy to mount the other two cards later since the riser board is prepared for it.

We figured that we needed to manage the heat between the cards so just like last time we slapped some case fans right on to the cards with zip ties. This turned out to be very effective with pushing the hot air out.

fans mounted

Good to go. Case fans mounted on cards.

The moment of truth

Everything was in place, time to hit the button!

fail

the look of failure

Goddammit that’s not what you want to see after a couple of hours working, obscure error messages when trying to boot up. It also said it couldn’t find any keyboard before jumping to that message.

We pulled out all of the risers and booted up without any GPUs (the HDMI is connected to the Intel card on the motherboard) and it worked. I remembered that I read somewhere that you should enable 4G Decoding in BIOS when hooking up many cards to the motherboard, so we did that. Then we installed one card at the time. On card 3 we got a Blue Screen of Death, but hopefully that was just a one time thing while Windows were figuring out what the hell we were doing with so many GPUs. Anyway, all four cards were successfully installed and up and running!

4x1060

Device manager showing 4×1060

Mining

Time to see what this thing could do. We loaded up our mining profile with MSI Afterburner and fired up Claymores miner. We usually mine with Genoil but Claymore is better when testing things out since it outputs easier to interpret hashing speeds.

mining with 4x1060

mining with 4×1060

And there we go. ~90MH/s hash rate and each card using ~80w. Interestingly the cards were running a couple of degrees cooler (54 C – 58 C) than in the first setup. This is probably due to that they are further from each other when mounted to the board as well as the case fans can more effectively push away the hot air.

Next time, installing two more cards and a more powerful (or secondary) PSU.

Building the Ghetto rig

My original plan was to:

  1. Mine some ETH with my gaming PC.
  2. Sell ETH for fiat currency on Kraken.
  3. Transfer money to my regular bank account.
  4. Build a proper rig.

More power

Check, check, check and now working on number 4. I got together with two friends and made an investment:

hardware for the ghetto rig

Hardware for the ghetto rig

We went with similar parts to what I used in my gaming PC with some exceptions.

  • Core i3 CPU. Cheap and doesn’t use much power, but not completely worthless. One could use even cheaper CPUs but we reasoned that since we might need to repurpose the rig in the not so distant future that might not be optimal.
  • ASUS z270-P motherboard. This guy managed to build a 8 GPU rig with it so it should work for our initial 6 GPU build.
  • 6x MSI GeForce GTX 1060 6GB OC. Cards are getting increasingly hard to find. This was the only 1060 model we found that we could buy six of. AMD cards haven’t been available for months, otherwise there might have been more value in rx570 cards.
  • Corsair RM750x PSU. This could be where we failed some. If we would be able to connect all GPUs to this PSU we might put to much strain on it. Each of those GPUs will use 85-100W and then you need some for the rest of the hardware. There is a plan B and C though. We have a 1050W PSU available that’s not being used to its’ full potential and we might swap that one for this RM750x. Plan C would be to fit in a secondary PSU and use two in the rig. The PSU situation is the same as with the GPUs, there are just no powerful PSUs in stock at the moment.
  • 2×4 GB Corsair Vengance DDR4. Maybe more than we need but same reasoning here as with the CPU.
  • Cheap WD Green SSD

Since we didn’t buy a case we also needed a power button. I ordered this from AliExpress a couple of weeks ago:

power button

Power button for when you don’t have a case

To be able to connect 6 GPUs to one motherboard you also need PCI-E risers. There are two PCI-E x16 and four PCI-E x1 slots on the board and with these risers you can connect x16 cards to x1 slots. The risers also makes it possible to get the cards (and heat) away from each other which is vital. They haven’t arrived yet though so for now we will only install two cards in the two available 16x slots.

pci-e risers

Risers that connects x16 cards to x1 slots

Putting things togheter

Inspired by all the milk crate rigs you find on the Internet, we went with this:

ghetto case

the ghetto case

It isn’t very well ventilated so we needed to do some work on it, but the motherboard and PSU went magically well inside:

z270-P and RX750 in case

z270-P and RM750x in case

ventilation for psu

Ghetto style ventilation for PSU

modded case

case modded and parts some fitted

pulp ball

To put some distance between the case and the motherboard we needed to raid my five year old daughters room for some ordinary pulp balls. I admit, we came pretty unprepared for this step but it worked out great. Six screws, each through the motherboard and the case with one pulp ball between the case and board. On the bottom where the screws were sticking out we put more pulp balls to hide the screws and get feet for the case. We also used them as distances between the side of the case and the PSU and then secured the PSU with a cable tie. Success.

the ghetto rig

the ghetto rig with two 1060 cards fitted

Once the GPUs where in place we slapped an old case fan directly to the cards to help further with driving out hot air in between.

Results

rig up and running

The ghetto rig up and running

It’s alive! And also mining ETH. We tweaked the cards with MSI Afterburner (power target 70%, memory clock up) and were getting ~23 MH/s per card at less than 60C temperatures after 6+ hours of mining.

ghettominer mining

Getting ~46 MH/s average hashrate

What we need to do next is to wait for risers to arrive, solve the PSU situation and modify the case to support four more cards.