The Monero network successfully conducted a scheduled upgrade on Nov. 30. Among other features, the RandomX mining algorithm was introduced to cripple ASIC machines and improve the efficiency of CPUs.
Specialized mining hardware has always been a hotly debated theme. Critics argue that they have a centralizing effect, as few companies in the world are able to manufacture ASICs. On the other hand, some suggest that ASIC-secured networks are less prone to suffering 51 percent attacks.
Monero firmly positions itself in the former camp. Its proponents often criticized ASICs and pledged to always maintain XMR resistant to specialized hardware — even at the cost of changing the mining algorithm.
RandomX is the result of that decision. The Proof-of-Work algorithm uses random code execution and memory-intensive techniques to discourage the development of ASICs. Its introduction renders all existing CryptoNight ASICs obsolete, while the added complexity aims to make the development of new machines both expensive and ineffective.
ASIC miners are not the only ones affected by the upgrade, however. The new algorithm is specifically optimized for CPUs, significantly penalizing GPU miners who wish to mine Monero.
A brief comparison shows that the hashrate for central processing units is seeing close to a tenfold increase. Conversely, Nvidia GPUs either retained or slightly improved their existing performance. For AMD cards the picture is even bleaker — most of them are about half as capable as before.
With the focus on CPUs, Monero developers believe that “the network will become more decentralized and egalitarian in the distribution of block rewards.”
However, this may be a double-edged sword. Monero has historically always been more CPU-friendly than any other major proof-of-work coin, leading to the spread of malicious native and browser-based mining software. Monero developers expect that RandomX will become more noticeable by administrators due to its memory hard approach, but the higher potential for gain may result in a renewed push for malware distribution.
Nevertheless, this uniqueness is positive from a network security standpoint. There exist few CPU-based mining farms that can be repurposed to attack Monero.
Monero hashrate more than tripled since the introduction of RandomX. Thus, it appears that CPUs already formed a significant chunk of its mining power. The majority is likely coming from legitimate miners, since the algorithm requires the installation of new software — a potentially troublesome task for botnets.