This past year I have received a lot of emails asking me about how to mine a cryptocurrency. There are lots of good guides out there for setting up real mining rigs. I used this consolidated guide last year but I recommend Cryptobadger for all current setups.
But if you really want to just test the waters with a machine you have laying around, I put together a very simple guide involving the least amount of technical prowess.
Step 1: Find, build or borrow a computer with a discrete video card made by either ATI (now AMD) or Nvidia. Radeon cards perform the best usually by an entire order of magnitude. Do not use a laptop because it will likely overheat and you may end up causing permanent damage to the machine (the only exception is a gaming laptop with fans/exhaust).
Step 2: Look at the Litecoin mining hardware comparison chart (even though it says Litecoin, you will end up with the same hashrate with Dogecoin or other Scrypt-based cryptocoins). Make sure to see what parameters and settings your discrete card functions best at.
Step 3: Download the GUIMiner fork for Scrypt-based cryptocurrencies (Litecoin and Dogecoin are the two largest in this space). Note: the original GUIMiner is designed for Bitcoin and will not work if you point it to a Scrypt-based pool.
Step 4: Look for a pool. You will unlikely be able to “discover” one of the blocks solo-mining with your own computer at this point, thus virtually everyone connects to a pool (a group of other miners) in which you collectively are rewarded for your share of hashing. For Dogecoin there are numerous pools, the one I’ve mentioned to my friends is Dogehouse. For Litecoin there are also many to choose from. The one I personally used in China was Coinotron. Note: pay attention to pool fees. Some of the fees can be relatively high, 5%. This is likely due to maintenance costs to prevent DDOS attacks from taking down the pool. Also PSA: if you plan to add a lot of hashrate I recommend joining a P2Pool to help decentralize mining.
Step 5: Sign up for a pool. When you register at one of the pools, be sure to use a password that only you know for the front-end otherwise someone can log in and modify the remittance address to their own. Once you have registered, you need to do two things:
1) Create a worker unit with a name like Alice.1 and give it a simple password like X. It doesn’t matter if someone knows that unit name or password, in fact they could actually point their cards to that address and help you mine, but that is unlikely : )
2) Look at the Getting Started section of the pool website. There you will find the information about stratum and pool connection info. You need to insert this information into the appropriate sections on GUIMiner.
Step 6: Insert settings. Again, find out what kind of video card your computer is using and look at the comparison chart (above) to find out what the best settings are for that card. If you use a Radeon you can use GUIMiner’s drop-down option and it will automatically insert the setting values. Otherwise you should just Google your video card and type “litecoin mining” or “dogecoin mining” (e.g., Radeon 7950 litecoin mining settings). It is important to look at the specific brand as some are better than others. CryptoBadger has a list of the best available to buy (or used).
Step 7: Test the settings. Once all of the fields are filled in GUIMiner and you have registered at a pool, be sure to click Start on the stratum server. Then move to the first tab and start the worker unit (GPU). You will instantly know whether or not the stratum connection is invalid as there will be a warning statement at the bottom with “Not Connected” next to it. If your card is actually working, you will audibly hear the fans blowing much faster and in the bottom right hand corner of GUIMiner you will see a hashrate (e.g., 600 kh/s). If you do not see a hashrate, it is not mining. If the Stratum connection is not working, you will not be credit with valid shares. In the bottom left of GUIMiner it will say how many shares have been accepted as well as stales/invalid. You can also check the mining pool interface/dashboard to see how each mining unit is doing.
Step 8: If the system is working, have it run for 5-10 minutes. See if it crashes. If it crashes, try to diagnose the reasons why. Did you try to run other applications at the same time? You will likely be able to utilize the system for any productive work as the GPU, CPU and system memory are preocuppied solving these “proof-of-work” math problems. So do not use your main work system. If your system crashes, you can ask the community websites (like LitecoinTalk) for help in troubleshooting the cause. In my experience the three most common problems are 1) heat dissipation, 2) power supply & 3) intensity settings are too high.
1) Heat dissipation. Most beginners do not realize that these GPUs will, at full load and intensity heat up to 70C+. My own reached over 80C and operated there non-stop for months. You need a way of dissipating this heat, either by cooling it down within a case (e.g., lots of fans or liquid cooling) or by building an open-air case (like a milk crate). If you are using more than one GPU you will also likely need a PCI-e riser to allow air flow in your system — if the cards are next to one another they will likely crash due to heat issues. Here is a how-to guide for installing risers. If you want to try liquid cooling, you can follow how my friend Silas did it several years ago with Bitcoin.
2) Do not underestimate how much electricity your GPUs will suck up. If tweaked properly for undervolting (using various software tools like MSI Afterburner and/or Trixx) you can reduce power consumption however if you’re a beginner you will likely need some spare wiggle room. There are endless threads about the best setup but do not skimp on a good PSU. A 750W from Corsair will power two Radeon 7950s without a hiccup. A 600W will likely not (perhaps creating a dangerous environment). Do not use any molex connectors or converters. Use a real power supply that has enough native PCI-e connectors to the board.
3) Each card has its crashing point. Push it too hard with too much heat or fail to give it enough electricity and it will crash. Another issue, and this involves guess-and-check is to incrementally increase the workload and intensity on the GPU. So if this is your first time, start at an intensity of 14 and build up from there. If you start at 20 you will likely crash the system and not be able to know exactly why (e.g., did it get too hot?). Pay attention to GPU temperature during this time, if it gets past 90C or increases from room-temperature very rapidly, it will likely crash due to heat-related issues.
Step 9: This short guide was to help you just test and start mining with whatever gear you had laying around. If you want to throw some real money at this endeavor, I recommend looking through CryptoBadger’s site and some of the mining forums out there. The Radeon 7950 is still probably the best value / hash / watt — but they are no longer made or sold in most countries (the exception is the HIS brand from Taiwan which can still be bought online sometimes). You can find others on Ebay and Craigslist (or 58.com if you’re in China).
Step 10: Install a remote-login tool such as LogMeIn so you do not have to connect your system permanently to a monitor or keyboard (do not give anyone that log in info). In most cases you can just leave the rig in a corner of a room near a window and check on it once or twice a day via the remote login.
Step 11: Calculate your hashrate and plug it into a Litecoin difficulty rating calculator. Then look to see how much it costs in electricity to operate your rig. Even if you are still generating dogecoin or litecoin each day, your electrical costs may create an unprofitable scenario (unless of course the tokens appreciate and/or the difficulty rating decreases).
Step 12: You have a binary decision making process. Either turn off the rig (remember, this was supposed to be just a test run) or leave it on. It can be a fun experiment to show your friends and family how distributed cryptoledgers actually work in terms of infrastructure, but you most likely do not want to bet the farm to build a server farm of these. [Don’t forget to get a Litecoin wallet or Dogecoin wallet to put those mined tokens in]
I have written a few other articles on mining before (see here and here). If you came here looking for Bitcoin mining, you are a couple years too late. For independent hobbyists, ceteris parebus it is mathematically impossible to profit off of GPU mining for Bitcoin. You can buy an ASIC but again, those are problematic in that there is a waiting list and you will likely not receive it in time to generate enough BTC to pay for the machine plus electrical costs. If you want to experiment you can buy a USB ASIC for Bitcoin mining (such as a Bi•Fury) that simply plugs into a USB slot and goes to work (you do need to manage the software, I recommend Bitminter as it is the easiest to setup with.)
Another problem with the ASIC from an investment standpoint is that it is a depreciating capital good. As the competition for hashrate continues (see this recent Bloomberg cover story) the network difficulty for Bitcoin increases dramatically by 10-30% at each reset (essentially every 2 weeks). Thus even if you do mine enough BTC and/or it appreciates in value to the point where you pay off the initial capital costs, you will unlikely be able to resell the ASIC to anyone (because why would a buyer want to purchase a product that is no longer profitable in hashrate?). Thus the only option you then have is to turn the ASIC box on to work on a different SHA256d proof-of-work cryptocurrency. CoinMarketCap has a list of other altcoins, nearly all of the ones currently listed after #15 are SHA256d-based.