Thanks to the gains in the Bitcoin price over the past several months, it has once again become popular to mine cryptocurrencies using graphics cards.
Like in the cryptocurrency bull run of 2017, this has contributed to a global shortage in high-end graphics hardware.
It has also caused the price of second-hand graphics cards to skyrocket.
We switched off our mining rigs when the cost of the electricity they consumed exceeded the value of the cryptocurrency we were mining.
However, we hadn’t got around to selling all of our graphics cards yet, and when Bitcoin broke through $50,000 (and most recently, through $60,000) we couldn’t help but wonder if dreams of crypto riches were still within our grasp.
RX 580 4GB mining rig – Ravencoin
AMD-based RX470, 480, 570, and 580 cards were all the rage back in 2017 as the most cost-effective options for getting into Ethereum mining.
Nowadays these cards are all but useless for mining Ethereum, unless you happened to buy versions with more than 4GB of video memory.
This is because the size of Ethereum’s blockchain (called a directed acyclic graph, or DAG) grew larger than 4GB in December 2020.
Some clever tricks from mining software developers allowed graphics cards with 4GB of memory to continue mining Ethereum with reasonable efficiency for a few more months after that, but with the DAG now sitting at over 4.1GB these cards’ days of mining Ethereum are officially over.
Enter Ravencoin, which has seen its price surge in February from around 50 satoshis (R0.45/RVN) to over 300 satoshis (R2.70/RVN) and given our old mining rig a new lease on life.
The table below shows the estimated earnings of our five remaining RX 580 graphics cards, using Nanopool and its Nanominer software on Ubuntu 20.04.
Without any optimisations, the graphics cards consume between 650W and 700W of power, which is expected to add around R1,200 to our electricity bill every month.
At an electricity tariff of R2.3406 per kilowatt-hour, our old mining rig is estimated to make a profit of just over R900 per month, so long as we can sell our mining rewards for over R2.68 per Ravencoin.
GTX 1080 mining rig – Ethereum
Amidst the 2017 Ethereum mining craze, there were some graphics cards you could still find at reasonable prices and in reasonable numbers, like the Nvidia-based GTX 1080 and 1080 Ti cards.
This was because mining software had not yet been updated to properly use GDDR5X memory and mining Ethereum on GTX 1080-series cards was significantly slower than on cheaper hardware.
In 2018, tweaks for graphics cards with GDDR5X memory started appearing online.
By then the price of cryptocurrencies had already come crashing down after reaching historical highs that January, making mining Ethereum far less attractive.
Today, with Ethereum at an all-time-high, our GTX 1080-based mining rig is printing money even though we had already sold two of its graphics cards.
With a few minor power optimisations, the cards draw an average of 475W. Over the course of a month, we expect the rig to cost us around R827 in electricity.