What does max-threads-hint do in XMRig?

max-threads-hint tells XMRig roughly how much of your CPU’s available threading capacity to consider when it automatically chooses a mining setup. It is a percentage-based hint, not a strict limit on CPU usage, and it may have no effect if your configuration already contains a saved thread setup.

What the number means

XMRig is mining software that can use your CPU, your computer’s main processor, to mine Monero. A mining thread is one stream of work running on that processor.

You set max-threads-hint inside the "cpu" section of XMRig’s configuration file:

"cpu": {
    "enabled": true,
    "max-threads-hint": 50
}

This is a configuration excerpt, not a complete configuration file.

The default value is 100. A value of 50 asks XMRig’s automatic setup to aim for a smaller thread allocation—roughly half of the available logical CPU threads. Logical threads are the processing slots your operating system sees.

You can also supply the hint when starting XMRig:

xmrig --cpu-max-threads-hint=50

Why it is only a hint

XMRig does not choose threads from that percentage alone. It also considers your processor and the mining algorithm, meaning the rules used to perform mining work.

Monero uses RandomX. For efficient mining, RandomX generally needs about 2 MB of L3 cache per mining thread. L3 cache is a small, fast memory area inside your processor.

That means:

• 100 does not necessarily make XMRig use every logical thread.
• 50 does not guarantee exactly half the threads in every setup.
• Raising the hint may add no threads if another hardware limit already determines the automatic choice.

For example, a processor with 16 logical threads may run fewer than 16 mining threads because its cache is better suited to a smaller number. More threads do not always mean faster mining.

Why changing it sometimes does nothing

This is the most important catch: max-threads-hint guides automatic configuration; it does not override an existing explicit thread profile.

XMRig can generate and save algorithm-specific CPU profiles. A RandomX profile commonly appears under "rx" in the "cpu" section. Once an applicable profile specifies the threads, changing the hint alone may leave those threads unchanged.

If your change seems ignored:

• Stop XMRig and back up your configuration file.
• Check for a saved RandomX thread profile.
• Remove the applicable generated profile if you want XMRig to choose again, or edit it deliberately for exact control.
• Restart XMRig and check its startup output for the actual mining thread count.

Be careful not to delete unrelated settings, such as your pool or wallet address.

What it does not control

A hint of 50 is not a promise of 50% CPU usage, half the electricity consumption, or half the heat.

The selected mining threads can still work continuously. CPU usage readings also include other programs, and power use does not scale neatly with thread count.

If your goal is a more responsive computer, a lower hint is a reasonable starting point. Then check responsiveness, temperatures, and mining speed rather than relying on the percentage alone.

The bottom line

Use max-threads-hint to influence XMRig’s automatic thread selection. Use an explicit thread profile when you need a precise count, and remember that a saved profile can make changes to the hint ineffective.