I've been toying with the idea of building an Ethereum mining rig for months. Ethereum is similar to Bitcoin insofar as the network has its own cryptocurrency, but goes further since it can also be used to build decentralized, blockchain-based apps. Its cryptocurrency is called Ether is used to pay for work done on the network. These Ethere tokens are created by running hashing algorithms in a process called mining.

But until the Ether price explosion last month, mining on the Ethereum network cost more in electricity than it generated in revenue. Following the meteoric rise of the world's second favorite cryptocurrency, however, I decided it was finally time to become a miner. So I strapped on my hardhat and hit the internet in search of the graphics cards that are the workhorses in most Ethereum mining rigs.

Yet as I found on site after site, GPUs were SOLD OUT and wouldn't be shipping for several weeks. As PC Gamer recently reported, it appears as though the altcoin mining boom had created a global GPU shortage. The question, however, is whether this drought has just begun, or if gamers and would-be miners will be out of luck for the foreseeable future.

As their name implies, GPUs are logic chips specifically designed for rending pictures and videos on a computer screen. They're mostly used for gaming to render 3D graphics in realtime. Unlike a Central Processing Unit (CPU), which is responsible for coordinating and executing commands from a computer's hardware and software, GPUs were designed so that they would be really efficient at repeatedly performing the same operation very quickly.

GPUs work well for rendering 3D games but they work great for mining Ethereum. Without getting too bogged down in the technical details, mining Ether requires a computer to continuously run a cryptographic hash function, which is a way to reduce an arbitrarily large amount of data (in this case a block on the Ethereum blockchain) to a datum of a fixed size (a string of so many numbers and letters). GPUs are great at running these hash functions over and over again.

Six RX 470 GPUs on an Ethereum mining rig. Image: Daniel Oberhaus/Motherboard

When Bitcoin was first proposed in 2009, its vision of the future was one where everyone could mine Bitcoin from their own personal computers. But this vision quickly died as Bitcoin succumbed to economies of scale. Today, dedicated hardware and massive Bitcoin farms in China means it's basically impossible to profitably mine Bitcoin without at least $10,000 in startup cash for hardware.

Ethereum's developers wanted to avoid this problem so they made the network "memory hard." This basically means that increasing the memory capacity for your mining rig won't actually give you a leg up. Importantly this means that Ethereum mining will always be limited to GPUs and will be resistant to specialized hardware and the application-specific integrated circuits (ASICs) that are used to scale Bitcoin operations.

This also means that GPUs have become a rare commodity.

According to Stefan Schindler, the Chief Technical Officer of Genesis Mining, the company buys its GPUs in bulk. Schindler wouldn't disclose just how many graphics cards are deployed at Genesis' Engima—heralded as the world's largest Ethereum mining operation—but said that the farming operation has grown significantly since it launched in 2015.

"Enigma started with an installation of about 700 GPUs and now consists of several larger buildings," Schindler told me in an email. "Obviously at this size the operation draws attention from the hardware manufacturers directly and we have agreements with them."

According to Schindler, the Enigma farm mostly consists of Sapphire 470s, which use a Radeon graphics card manufactured by Advanced Micro Devices (AMD). He said that Genesis is aware of the GPU shortage, but also noted that in the world of altcoin mining, this is nothing new.

"Short spikes of mining profitability creating a large demand of GPUs first happened in October 2013 when the Litecoin price went up," Schindler said. "After the spike was over, many home miners sold their GPUs on Ebay which caused a lot of headache for manufacturers who tried to ensure their sales of their current products."

This is already happening now with the latest Ethereum boom. But rather than people trying to offload their GPUs after a mining boom, used mining rigs are being listed on Ebay and Craigslist for a several times their list price due to high demand. But buying used graphics cards can be a risky bargain—GPUs used for Ethereum mining are usually running around the clock, which wears them out far quicker than when they are just used for gaming.

On the other hand, Ethereum is going to switch from Proof of Work to Proof of Stake at some point in the next year or so, which is essentially a way to lower the resource intensity of the Ethereum network. However it will also have the side effect that the GPU mining rigs currently being used on the network will become more or less useless. At that point, these miners will have two choices: either use their rigs to mine other altcoins like ZCash, or try to sell them online.

All Radeon RX 470 GPUs on Newegg are sold out. Screengrab: newegg.com

This cycle of boom and bust is difficult for both chip manufacturers like AMD, as well as PC gamers who usually only need one or two GPUs to power their rigs. To temper these GPU shortages, Schindler said Genesis is working with hardware designers to create proprietary graphics cards that are optimized for mining and don't compete with those used for gaming.

"I really don't want to take GPUs from gamers," Schindler added.

Although AMD told CNBC that making GPU's for gamers remains its priority, it is also being reported that the chip manufacturer is planning to make dedicated altcoin mining GPUs. AMD did not respond to Motherboard's request for comment.

After a lot of research and settling on computing power, I was lucky enough to secure six new GPUs for my mining rig. This was toward the beginning of Ethereum's dizzy growth period last month, and a cursory scan shows that GPUs are even scarcer now. Indeed, the GPUs I had bought ended up selling out just hours after my purchase in early May.

With no end to the altcoin boom in sight, this GPU shortage is bad news for gamers, who will likely have to wait a while before they are able to easily get their hands on a decent, affordable graphics card.