Building a Crypto Mining Rig

Hey Steemians!

I thought I’d share my experience in building a hobby mining rig. Through some trial and lots of error, she seems to be running well and is very stable.

I had initially looked into cryptocurrencies about a year and a half ago. I discovered dogecoin at the time, and started mining on my laptop for a bit, just to get a feel for it. Sadly, I stopped mining in about two days and forgot all about it. Then 2017 happened. There I was… Hearing all the news about the late 2017 crypto-currency boom. Bitcoin up near $20k? Wow! Honestly, I was kind of kicking myself in the butt for not investing the year prior. Oh well.

Nevertheless, I became interested in crypto again after reading all the hype. Being the tech geek that I am, I thought it would be a great experience to build a crypto mining rig. Being the impulse buyer that I am, I immediately began purchasing parts. My initial intent was a power-hogging 6 GPU rig running Radeon 7990s. However, after exhibiting some self-restraint, I stopped the project at only 3 Radeon 7990s (for now).

Parts & Pieces

I’ve come to learn that building a mining rig takes a bit of research, so you don’t buy two motherboards, but all-in-all it was a relatively easy venture. I began by ordering the motherboard processor combo. Working with ATI cards, I settled on the MSI Z270 SLI Plus. Mistake. I found that out later-on. I paired my motherboard with an Intel Pentium G4400 processor because, let’s face it, I don’t need 8 cores when the GPUs are doing all the work. In addition to those, I ordered one XFX Radeon 7990 to begin with. The market is ripe with over-priced GPUs right now. It took a bit of time to find a used 7990 at a decent price. I had a Sandisk SSD laying around already, so I was able to skip purchasing another. I also acquired a open-air mining case from Amazon. In fact, most of my purchases came from Amazon. Additional parts needed are PCI risers, a semi-hefty power supply (I went with the Corsair RM1000i for now, with plans to add another when I decide to get three more GPUs), thermal paste, high-end thermal pads (to refurb GPUs), 5 and 120mm cooling fans.

First Signs of Trouble

After completing the initial build, installing windows 10 and trying to get everything working, I realized the MSI Z270 SLI Plus onboard graphics and the Radeon 7990 DO NOT GET ALONG! I got repeated black screens. I also could not downgrade to Windows 7 on the SLI plus, no matter what Flash Drive / driver injection method I used. It was at this point, I went back to the drawing board. I realized that my XFX Radeon 7990 was getting excessively hot, so I ordered thermal paste and pads as well as a new cooling fan assembly. After conducting some additional research, I settled on a replacement motherboard: the ASUS Prime Z270-A. This one was listed as compatible with multiple GPUs and also give the end-user the option to turn off the onboard LEDs (an option not available on the Z270 SLI Plus). I keep the rig in my bedroom. Bright LEDs are super irritating at night! At the same time, I found two more Radeon 7990s (one XFX and one MSI), which I purchased. Two days later (thank you Amazon Prime), I received the motherboard and both additional graphics cards.

I swapped out the motherboards, disabled all of the non-essential settings in BIOS on the ASUS, including the rainbow bright LEDs, refurbished the overheating 7990 and installed the two additional GPUs. Once everything was wired up, I powered her on. To my amazement, with the DVI cable attached to the refurbished 7990, it booted into Windows and actually had picture on the monitor! Hallelujah! The problems didn’t end there, however. I continued to get black screens, though much less frequently. I finally decided it was time to try Ubuntu instead of Windows 10… NOPE! Windows 7 was next. Following the driver injection procedures for USB 3.0 (all over the internet) and routing the USB keyboard and mouse through PS2 instead of USB, I was finally able to get the Windows 7 setup to begin without throwing driver errors. Finally. I’ll admit, on a rig with that much power plus an SSD, it was the fastest Windows 7 install I have ever seen!

Let’s Get Mining!

Once in Windows 7, I had to find a compatible, but not-too-new, set of drivers for the Radeon 7990s. I settled on a 2015 version that seems to be stable. Following the driver install, I fired up Claymore 10.2… Mistake. The GPUs would run on 10.2 for about 10 minutes before they began crashing, one at a time. Incorrect shares were also very frequently found. Time to downgrade. I went back to Claymore 9.7, set up to mine Monero. I had been mining Bytecoin for several weeks on my laptops, but became bored after only receiving 200 Bytecoin. I fired up Claymore and, low and behold, without under or overclocking, had a hash rate of 3100 H/s (3.1 kH/s). Wow! That’s literally twenty times faster than my two laptops combined! Imagine what 6 GPUs would look like!

I soon realized that my GPUs were heating up pretty quickly at the Radeon 7990 stock 1000 MHz core clock and 1500 MHz memory clock. I had to cool her down a bit, as my air conditioning was struggling to overcome the effects of this new little “space heater”. I downloaded an older version of MSI Afterburner, since Radeon software sucks, and under-clocked my core clocks to 950 MHz and the memory clocks to 1400 MHz. The hash rate settled in at about 2860 H/s. From there, I let her run. The first round went 68 hours stable before I got a black screen and 0 H/s. I made a couple tweaks in the BIOS, setting PEGs back to Gen 2. She runs great now. The second run went 78 hours before I manually rebooted for stability purposes. I have since set up an auto reboot for every 72 hours as well as autorunning Claymore 9.7 and MSI Afterburner on startup.

Additions

I needed a way to monitor my rig from work. I found a program called Team Viewer that allows me to remotely control the rig from my laptop at work or even from my android. Now I am able to log in anytime and make sure all is running smoothly, adjust clock and GPU fans peed as I see fit.

Next Steps

I plan to add three more cards to the rig. With any luck, the astronomical price of GPUs will fall sometime in the near future. In addition, as you can see from the pic, I need to do some cable management. Yes, I have zip ties. I was just so excited to get this thing running that I skipped that part! After some additional research, I may decide to sell of my rig or the GPUs and build another or implement different GPUs. Don't get me wrong, I love these GPUs. They pump out a pretty hefty hash rate, stay relatively cool (60-70 celsius) and are fairly quiet, even at 60% fan speed.

Afterthoughts

I’ll admit, I didn’t expect to make a LOT of money in this venture, but since I don’t pay the power bill (currently drawing 1100 watts at the wall), I figured it would be a fun project and a way to begin a cryptocurrency investment. If all else fails… Hey, I have a really badass gaming computer at my disposal!

Warnings

This is NOT, by any means, an energy efficient rig! I targeted the power-hogging Radeon 7990’s for their high hash rates. I could have run more efficient ATI cards, or even gone with Nvidia cards to mine ether, but I was impressed by the hash rate benchmarks on these cards. I’m currently drawing 1100 watts (+/- 5%) at the wall. I’d expect Nvidia cards would be closer to 700-800 watts.
Power supplies are a critical element in this process. Currently, running three 7990’s I’m close to the upper limits of the RM1000i. I plan to add a secondary RM1000i in the near future to take some of the load off the first and increase the PSU’s efficiency.

The Rig

(1) ASUS Prime Z270-A
(1) Intel Pentium G4400 Processor @ 3.30 GHz
(1) Corsair Vengeance LPX 8GB RAM
(1) Corsair RM1000i Modular Power Supply
(1) Victony 6-Pack PCI Riser 1x to 16x
(1) Veddha 6 GPU Miner Case
(2) XFX Radeon 7990 6GB
(1) MSI Radeon 7990 6GB  I like these better. They are slim and stay cooler than XFX.
(5) Arctic Bionix F120 Gaming Fan
(1) TreeStar Electricity Usage Monitor
(1) YueYueZou Desktop PC Power Button With USB