The following instructions assumes you have a Nintendo Switch running Atmosphère, updated to at least the latest stable version.

• Copy the config and atmosphere folders at the root of your SD card and reboot the console.
• The sysmodule will be active and running out of the box.
• Note: sys-clk-overlay requires to have Tesla Menu and nx-ovlloader installed and running.

To create a new preset, just edit /config/sys-clk/config.ini on your SD card (see Config).

Note: If you're using ReiNX, you need to rename the atmosphere folder to ReiNX and move out the boot2.flag file next to exefs.nsp

How does it work

The sysmodule overclocks and underclocks the CPU, GPU and RAM of the console depending on the title currently running and docked state. When you run a game, sys-clk will read its preset it and automatically overclock (or underclock) the system for you.

All frequencies can be set for both docked and handleld mode, making 6 values per preset. These values are capped for safety reasons:

• CPU (capped at 1785MHz).
• GPU (capped at 460MHz without a charger, clocks up to 768MHz require a charger, clocks higher than 768MHz require the official charger).
• RAM (capped at 1600MHz).

These limits ensure that the console won't be damaged due to overclocking.

Relevant files

• /config/sys-clk/config.ini - Config file allows one to set custom clocks per docked state and title id, described below.
• /config/sys-clk/log.txt - Log file where the logs are written if enabled.
• /config/sys-clk/log.flag - Log flag file enables log writing if file exists.
• /config/sys-clk/context.csv - CSV file where the title id, profile, clocks and temperatures are written if enabled.
• /switch/sys-clk-manager.nro - sys-clk manager app (accessible from the hbmenu).
• /switch/.overlays/sys-clk-overlay.ovl - sys-clk overlay (accessible from anywhere by invoking the Tesla menu).
• /atmosphere/contents/00FF0000636C6BFF/exefs.nsp - sys-clk core sysmodule.
• /atmosphere/contents/00FF0000636C6BFF/flags/boot2.flag - sys-clk core sysmodule.

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
  • Charger specific config (USB or Official) handheld_charging_usb_X or handheld_charging_official_X
  • Non specific charging config handheld_charging_X
  • 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:

Capping

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

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:

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