Does RandomX run better on AMD Zen or Intel CPUs and why?

AMD Zen CPUs often run Monero’s RandomX more efficiently than comparable Intel CPUs, especially desktop Ryzen models with plenty of L3 cache. But there is no universal winner: the exact chip, memory setup, power limits, and mining software matter more than the brand alone.

Why RandomX often favors AMD Zen

RandomX is Monero’s mining algorithm—the work your computer does to help secure the network. It has been used since November 30, 2019, and is designed to favor general-purpose CPUs rather than specialized mining chips.

Its workload mixes unpredictable instructions with frequent memory access. That makes cache, the small, fast memory inside your CPU, especially important.

Each RandomX mining thread—one stream of work—needs about 2 MB of L3 cache for good performance. Many AMD Zen desktop and server processors offer generous L3 cache relative to their core count.

For example, a CPU with 32 MB of L3 has cache capacity for roughly 16 mining threads. That is a useful starting point, not a promise that 16 threads will be fastest. Cache is shared with other work, and its physical layout matters too.

Zen chips also commonly offer strong efficiency on this workload. You may get more mining work for each watt of electricity, particularly with sensible power limits.

Why more cores do not automatically win

Intel can be competitive, but a higher advertised core or thread count does not guarantee better RandomX performance.

On Intel processors that combine performance cores and efficiency cores, those cores have different capabilities. Adding every available thread can increase competition for cache and memory without delivering a matching speed gain.

AMD has its own complications:

• Cache location matters. On multi-chiplet Zen processors, L3 is divided between small groups of cores, rather than being equally close to every core.
• Extra threads have limits. Running two threads per core can help, but only when enough resources remain available.
• Extra cache is not everything. AMD X3D models add cache, but clock speeds, power limits, and price still affect their value for mining.

You should compare specific processors, not assume that every Ryzen beats every Core—or that every newer generation is better.

Memory and settings can change the result

RandomX’s fast mode uses a dataset of about 2,080 MB, alongside a 256 MB cache. Light mode uses the smaller cache without the full dataset, but runs much more slowly.

These memory structures are separate from the CPU’s L3 cache. Enough system RAM is necessary, but simply adding more RAM will not keep increasing mining speed.

For a fair AMD-versus-Intel comparison, look for tests with:

• The same mining software and comparable settings.
• Similar memory configurations.
• Clearly stated CPU power limits.
• Whole-system wall power, not just estimated CPU power.

Compare both hashrate, meaning mining calculations per second, and hashes per watt, meaning work done for each unit of power. The fastest CPU may not be the cheapest to run.

The bottom line

AMD Zen is often the stronger starting point for RandomX because of its cache capacity and efficiency. Still, check measured results for the exact chips you are considering.

For browser mining, be especially cautious: native mining benchmarks do not directly predict browser performance. Browser execution limits, memory handling, and available optimizations can change the comparison. Test your actual setup, and use a live mining calculator before treating either brand as a profitable purchase.