There was a time when anyone with a graphics card--or even just a CPU--could mine some Bitcoin and turn a profit. That time has long since passed; these days, you need an application-specific integrated circuit (ASIC) setup to even have a shot at making some money. But why did Bitcoin go from being an easy money maker to something few can afford to mine?
The answer lies with one of Bitcoin’s basic principles, which makes the cryptocurrency harder to mine as it grows in popularity. That way, having a bunch of people mine Bitcoin won’t undermine its value. It’s almost like circulating a limited number of U.S. dollars so each one is worth more, comparatively, instead of thinking you can create wealth by literally printing money.
Not that you have to print Bitcoin, of course. Instead, when you’re “mining” the cryptocurrency, you’re basically tasking whatever device you’re using with solving a bunch of math problems.
How Bitcoin Is Mined
Bitcoin, like seemingly every other technology these days, is based on the blockchain. The blockchain is pretty much what it sounds like: a series of interconnected “blocks.” In Bitcoin’s case, these blocks are used as transaction ledgers that make sure every exchange of the cryptocurrency is legitimate. Instead of trusting a central figure, like you do with traditional currencies, you’re trusting the math behind Bitcoin to ensure everything is on the up-and-up.
Doing all that math requires some computational resources. That’s what your mining rig is--a system that downloads the blockchain, does a bunch of math, and assures the rest of the Bitcoin ecosystem that a given transaction was legitimate. In exchange for devoting your rig to preserving this system, you’re given a certain transaction fee as well as a subsidy of new coins--hence the “mining” metaphor that compares earning Bitcoin to digging up something like gold.
Unlike gold, however, Bitcoin isn’t a naturally limited resource. One could theoretically design a cryptocurrency that allows someone to earn as much as they want as long as they have the hardware to back it up. But that would devalue each unit (or “coin” for most cryptocurrencies). Instead, Bitcoin was designed in a way that ensures the creation of new coins is stable over the long term. As more Bitcoin is created, each individual Bitcoin gets harder to mine.
Weighing The Costs Of A Mining Rig
This increasing complexity makes it harder for general hardware, like an off-the-shelf CPU or GPU, to mine Bitcoin. The days of being able to mine Bitcoin while your system would otherwise be idle are pretty much over; you’re not going to make any real money that way. Instead, dedicated Bitcoin miners have to create “mining rigs” devoted specifically to Bitcoin mining.
Each mining rig is the result of basic cost-benefit analysis. You have to think about how much the system will cost to assemble, how much it will add to your power bills, and how much you expect to make in real-world money before you actually build the thing. (We explained that process as it relates to Ethereum, another popular cryptocurrency, here.) It doesn’t make sense to spend an exorbitant amount of money up front, and monthly, on a rig that makes a pittance each month.
Combine the need to pay for parts and power with the increasing complexity involved with mining Bitcoin, and you have a situation where CPUs and GPUs have been effectively pushed out of the mining game. To answer the question in the headline: You can, technically, mine Bitcoin with your PC. The problem is that doing so would be like trying to mine gold with a soup ladle while other people are out there with heavy equipment and teams of workers who all specialize in mining.