The Homebrew Litecoin Mining Project

It’s hard not to be mesmerized by Bitcoin, the peer-to-peer digital currency developed by the mysterious Satoshi Nakamoto (presumably a pseudonym). The Bitcoin network went online as the first truly successful attempt at creating virtual money in early 2009, though it received little attention until last year when the value of the currency rose from $ 13 to $ 1,000 on public exchanges like BTC-E.

Many who had mined early and actually kept their loot suddenly found that they were millionaires. Others stood up for not jumping in earlier, but one thing was clear: everyone wanted to participate – and not necessarily get rich quick. For hardware enthusiasts like me, this is just another opportunity to build and tweak a system, although I wouldn’t complain about making a few dollars in the process.

There are two ways to get your hands on bitcoins: buy them or mine them. Mining bitcoins requires a lot of effort (computing power) to create (mine) a new currency. The underlying process behind mining is extremely complicated. For brevity, I’ll skip most of the detailed information and break it down into layman’s terms instead. If you’d like the long version, I recommend reading or looking at this article by Michael Nielsen:

Essentially, computing power is used to solve complex math problems, and miners who do them first are rewarded with bitcoins. Traditional desktop CPUs were previously used to solve these problems. However, as more and more people entered mining, it took more computing power to get similar payouts. People quickly realized that GPUs could solve these problems 50 to 100 times faster than CPUs.

Despite the increase in mining speed, GPUs turned out to be less than ideal because of their power consumption and the resulting heat. Bitcoin miners eventually switched to FPGAs (Field Programmable Gate Arrays), which resulted in a five-fold increase in consumption. By mid-2012, FPGAs lost their appeal with the introduction of fully functional application-specific integrated circuit systems (ASIC), today’s standard for Bitcoin mining.

Needless to say, mining bitcoin is now a serious undertaking. Don’t waste your time unless you are ready to compete with professional mining companies like this one. Fortunately, however, the success of Bitcoin has spawned many other virtual currencies, with nearly half a dozen classified as “major” cryptocurrencies on Wikipedia. Of these, Litecoin is one of the most popular alternatives to Bitcoin.

As the name suggests, Litecoin is based on Bitcoin’s technology, but differs in that it targets a faster block rate and uses Scrypt as a proof-of-work scheme when mining. In contrast to the Bitcoin network, which can only have 21 million coins at a time, the Litecoin network can have 84 million coins once they are all mined. To use a common analogy, people say Litecoin is the silver to Bitcoin’s gold.

Since the network is still in its infancy, Litecoin mining is still financially viable and is best carried out with conventional desktop graphics cards, as there are (yet) no ASIC Litecoin miners.

If you want to consider virtual coin mining a hobby, litecoins are probably your best bet right now. We’ll show you how to start selecting and configuring the hardware and software you need. Also note that we are targeting this article at PC enthusiasts who likely have replacement hardware and are separating our project from milk crate builds. This seems like the most logical approach for us to get started.

Prepare the hardware, build a Litecoin miner

Before building from scratch, I recommend doing an inventory of your replacement components. It can’t hurt to see if your friends or family have old parts either. As a hardware enthusiast, I already had access to an enclosure, retired hard drives (solid-state drives are a waste here), an old optical drive, and a replacement keyboard. I also got an AMD Sempron 140 from a friend. As you will soon learn, CPU performance is largely irrelevant.

GPUs are important if you want to mine Litecoins. The Litecoin Hardware Comparison Wiki does a great comparison of mining performance, but here’s the short one: Forget about Nvidia and target the AMD Radeon R9 series. You get the best performance with a 290x card, but it’s also the most expensive. The 7950 is another popular choice, but their age makes them harder to come by.

The R9 280x is currently considered the most popular choice for Litecoin mining in terms of price and performance. Unfortunately, between vacation shoppers and coin workers buying the R9 series, you can expect a price premium of over $ 100 than when the cards were first launched. For about a month it was virtually impossible to find cards in stock at a major online retailer, but the market is not quite as dry now.

I bought two 290x GPUs and one 280x GPU from three different manufacturers – not because I wanted different brands, but it’s all I could get my hands on at the time. In particular, I use a HIS 290x, another 290x from Sapphire, and a PowerColor 280x. The two 290x cards are essentially identical as both reference designs are using AMD’s cooling solution, while the 280x has an aftermarket heat sink.

Surprisingly, most mining tutorials recommend putting your hardware in a plastic box and cooling it with a box fan, but that didn’t work for me at home. The case (or milk crate) you choose will determine the capacity of your miner. I used Cooler Master’s Cosmos II – partly because it’s my favorite case, but mostly because it’s what I had on hand. Plus, it’s a huge case, and that means more GPUs can fit.

With three cards from the R9 series in my miner, I opted for a motherboard with four PCIe x16 slots (Gigabytes GA-990FXA-UD3). While your choice of memory isn’t particularly important – I bought two 4GB sticks of Crucial Ballistix memory because it was on sale – you should definitely look for power supplies that have the stated power and 12V Need to compare rail performance with that of your GPUs.

Last specifications of our Litecoin miner:

  • AMD Sempron 140 + retail heat sink
  • Gigabyte GA-990FXA-UD3 Mobo
  • 2x4GB Crucial Ballistix 1866MHz RAM
  • 400 GB hard drive
  • HIS Radeon R9 290X
  • Sapphire Radeon R9 290X
  • PowerColor Radeon R9 280X
  • x16 to x16 PCI Express riser cables
  • SilverStone ST1500 power supply
  • Cooler Master JetFlo 120mm + NMB 120mm fan
  • MediaLink Wireless-N USB adapter
  • Cool Master Cosmos II
  • Windows 7 64-bit

I chose SilverStones ST1500, a 1500W, 80 PLUS Silver device. Aside from being able to meet my power needs, the ST1500’s modular design is useful for maximizing airflow. I have had great luck with SilverStone power supplies over the years and this model has proven no different. Whatever you do, don’t skimp on here. Get something valued for more than you need. You’ll be surprised how much power three high-end GPUs consume.

These parts are not necessary, but I found them to be worth buying. I took a single PCIe x16 riser cable to free up the cards for cooling as much as possible. I also bought the Tripp Lite UltraBlok Isobar protection, a Medialink Wireless-N-USB adapter (Ethernet is fine, wireless was just more practical for me) and a Kill-A-Watt power consumption monitor to see exactly drawing how much electricity your miner uses.

Installation and cooling tips

After slimming it down, I updated the Cosmos II’s pre-installed fans. I first replaced the stock 200mm intake fan with a Specter Pro from BitFenix, which supposedly moves more air at 148.72 CFM at 900 RPM . It was a disappointment, but since the fan felt like it was barely moving air and the main fan was supplying air to the graphics cards, this wasn’t enough.

I replaced the BitFenix ​​fan with a 120mm x 38mm NMB model 4715KL-04W-B49 that came from a Dell tower server. What’s more important here than a specific fan recommendation is to state that the noise of your case fans should be a secondary issue for airflow, not least because your GPUs are likely to be louder than any other fan. So don’t let that stop you from using one with a high dBA rating.

Along with a second NMB fan (120mm x 25mm rated at 92 CFM) that bleeds air out of my GPUs from the left panel, I used three Cooler Master JetFlo 120s as top inlets, another one as rear outlet and one at the front as an inlet and two more to blow air into the lower chamber for the power supply (picture below). This may not be an “ideal” layout on paper as hot air rises, but it is also not a traditional layout.

I came up with this configuration after countless hours of trial and error. Without removing the side bezel and using a case fan to flood the case with air, this is the best layout possible given the hardware and cooling available. If you can’t keep temperatures in check with case fans, you can cut a few degrees off the top by replacing the GPU’s standard thermal paste.

Keep in mind that if you are using a high performance fan, you will want to plug it directly into your power supply instead of a motherboard header or low power fan controller to avoid damage.

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