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FPS cap calculator: where to cap the frame rate with G-Sync, FreeSync or Reflex

Your refresh rate and your setup in, the cap and where to set it out. The same rules as our game guides.

Hz

Variable refresh on the monitor

Reflex or Anti-Lag 2 in the game

...

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01Where the numbers come from

Three setups, the same as in our CS2, Valorant and Fortnite guides.

  • No G-Sync or FreeSync: no cap. V-Sync off, Reflex or Anti-Lag 2 on, and the frame rate as high as it goes. The lowest input lag; the price is tearing.
  • G-Sync with Reflex: G-Sync and Vertical sync on in the driver, V-Sync off in the game. Reflex then caps the frame rate just under the refresh rate by itself: about 138 FPS at 144 Hz and about 224 at 240 Hz. NVIDIA says this is slightly slower than running uncapped; in exchange the picture never tears.
  • G-Sync without Reflex, or FreeSync: cap by hand at least 3 FPS under the refresh rate, in the game’s own limiter rather than the driver’s.

The guides: CS2, Valorant, Fortnite.

02Why the cap sits under the refresh rate

Above the refresh rate, variable refresh stops working.

G-Sync and FreeSync match the monitor to the game only while the frame rate stays inside the monitor’s range. At or above the refresh rate, V-Sync takes over and adds a queue of frames, which is the input lag people try to avoid. A cap a few frames under the refresh rate keeps the game inside the range.

The 3 FPS margin comes from tests on G-Sync. On FreeSync it is a reasonable guess, not a measurement.

03Check the refresh rate first

A cap for 144 Hz does nothing for a monitor that Windows runs at 60 Hz.

The number above is measured on the screen this window is on. If it is lower than your monitor can do, fix that first: the monitor refresh rate test shows how.