Skip to content
develop
Switch branches/tags
Code

sys-clk

Switch sysmodule allowing you to set cpu/gpu/mem clocks according to the running application and docked state.

Installation

The following instructions assumes you have a Nintendo Switch running Atmosphère, updated to at least the latest stable version. Copy the atmosphere, and switch folders at the root of your sdcard, overwriting files if prompted. Also copy the config folder if you're not updating, to include default settings.

Note: sys-clk-overlay requires to have Tesla installed and running

Relevant files

  • Config file allows one to set custom clocks per docked state and title id, described below

    /config/sys-clk/config.ini

  • Log file where the logs are written if enabled

    /config/sys-clk/log.txt

  • Log flag file enables log writing if file exists

    /config/sys-clk/log.flag

  • CSV file where the title id, profile, clocks and temperatures are written if enabled

    /config/sys-clk/context.csv

  • sys-clk manager app (accessible from the hbmenu)

    /switch/sys-clk-manager.nro

  • sys-clk overlay (accessible from anywhere by invoking the Tesla menu)

    /switch/.overlays/sys-clk-overlay.ovl

  • sys-clk core sysmodule

    /atmosphere/contents/00FF0000636C6BFF/exefs.nsp /atmosphere/contents/00FF0000636C6BFF/flags/boot2.flag

Config

Presets can be customized by adding them to the ini config file located at /config/sys-clk/config.ini, using the following template for each app

[Application Title ID]
docked_cpu=
docked_gpu=
docked_mem=
handheld_charging_cpu=
handheld_charging_gpu=
handheld_charging_mem=
handheld_charging_usb_cpu=
handheld_charging_usb_gpu=
handheld_charging_usb_mem=
handheld_charging_official_cpu=
handheld_charging_official_gpu=
handheld_charging_official_mem=
handheld_cpu=
handheld_gpu=
handheld_mem=
  • Replace Application Title ID with the title id of the game/application you're interested in customizing. A list of games title id can be found in the Switchbrew wiki.
  • Frequencies are expressed in mhz, and will be scaled to the nearest possible values, described in the clock table below.
  • If any key is omitted, value is empty or set to 0, it will be ignored, and stock clocks will apply.
  • If charging, sys-clk will look for the frequencies in that order, picking the first found
    1. Charger specific config (USB or Official) handheld_charging_usb_X or handheld_charging_official_X
    2. Non specific charging config handheld_charging_X
    3. Handheld config handheld_X

Example 1: Zelda BOTW

  • Overclock CPU when docked or charging
  • Overclock MEM to docked clocks when handheld

Leads to a smoother framerate overall (ex: in the korok forest)

[01007EF00011E000]
docked_cpu=1224
handheld_charging_cpu=1224
handheld_mem=1600

Example 2: Picross

  • Underclocks on handheld to save battery
[0100BA0003EEA000]
handheld_cpu=816
handheld_gpu=153
handheld_mem=800

Advanced

The [values] section allows you to alter timings in sys-clk, you should not need to edit any of these unless you know what you are doing. Possible values are:

Key Desc Default
temp_log_interval_ms Defines how often sys-clk log temperatures, in milliseconds (0 to disable) 0 ms
csv_write_interval_ms Defines how often sys-clk writes to the CSV, in milliseconds (0 to disable) 0 ms
poll_interval_ms Defines how fast sys-clk checks and applies profiles, in milliseconds 300 ms

Capping

To protect the battery from excessive strain, clocks requested from config may be capped before applying, depending on your current profile:

Handheld Charging (USB) Charging (Official) Docked
MEM - - - -
CPU - - - -
GPU 460 768 - -

Clock table (MHz)

MEM clocks

  • 1600 → official docked, boost mode, max clock
  • 1331 → official handheld
  • 1065
  • 800
  • 665

CPU clocks

  • 1785 → max clock, boost mode
  • 1683
  • 1581
  • 1428
  • 1326
  • 1224 → sdev oc
  • 1122
  • 1020 → official docked & handheld
  • 918
  • 816
  • 714
  • 612

GPU clocks

  • 921 → max clock
  • 844
  • 768 → official docked
  • 691
  • 614
  • 537
  • 460 → max handheld
  • 384 → official handheld
  • 307 → official handheld
  • 230
  • 153
  • 76 → boost mode

Notes:

  1. GPU overclock is capped at 460Mhz in handheld and capped at 768Mhz if charging, unless you're using the official charger.
  2. Clocks higher than 768MHz need the official charger is plugged in.