# Toolbar

### Power meter

When power meters are enabled, Rack measures the amount of time spent processing each module in *mS* (millisamples).
In many ways, this is analogous to the module power limit imposed by hardware modular synthesizers in *mA* (milliamperes).

The total amount of time spent processing all modules must equal **1000 mS**.
To achieve this, the [Audio](Core.md#audio) module from [Core](Core.md) uses your audio device's high-precision clock to regulate Rack's processing loop, so it idles for some amount of mS until this total is met.
If the Audio idle time falls to an average of 0 mS over its block size, an audio stutter will occur.
This can be caused by other modules consuming lots of mS.

### Internal sample rate

Rack advances the state of each module by the duration specified by Rack's internal sample rate.
A higher sample rate decreases the timestep, resulting in more accurate analog circuit modeling at the expensive of more mS consumed by all modules.