Latitude 7420 or 7520 CPU Frequency Drops to Lower Than 1 GHz When Running on Battery

Summary: The article provides information about the CPU frequency drop when running Latitude 7420 or 7520 on battery only.

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Symptoms

When a Latitude laptop is running on battery only, the CPU may run at a low power state and cause the CPU frequency drops to lower than 1 GHz in Task Manager. The issue occurs even when the CPU is busy.

CPU frequency drops to lower than 1 GHz in Task Manager 

Affected Platforms:

  • Latitude 7420
  • Latitude 7520

Cause

The battery reports a low Maximum Power Point (MPP) and Sustainable Power Point (SPP) value to Embedded Controller (EC).

Resolution

Updating to BIOS version 1.38.1 or later on the computer resolves the issue. To download and install the BIOS, reference BIOS Update Guide.

Affected Products

Latitude 7420, Latitude 7520
Article Properties
Article Number: 000255870
Article Type: Solution
Last Modified: 13 Nov 2025
Version:  3
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