Make sure the display you are measuring has been warmed up for a suitable amount of time, at least 30 minutes. Ideally you would run some dynamic content like a game, video or perhaps leave the full screen version of this TestUFO.com test running if you want. The OSRTT software will warn you if it detects you might not have warmed up for long enough
Make sure that you have monitor features like blur reduction mode (which would strobe the backlight) or any local dimming disabled. These would cause variations in the light measurement and lead to errors in calculations.
Set your graphics card to the refresh rate you want to measure:
For PC gaming usage it is best to set it to the maximum the screen will support. The software will allow you to measure the impact of VRR (Variable Refresh Rates – G-sync and FreeSync) where the frame rate drops below this, by limited the FPS settings, so you do not need to change the refresh rate setting for that.
You may also want to test the screen at a fixed refresh rate for certain situations. For instance, you may want to set the graphics card refresh rate to a fixed 60Hz input, and disable G-sync / FreeSync to simulate the performance if you had a Blu-ray player or 60Hz games console connected. Likewise you could also set the refresh rate at 120Hz to capture the performance for a 120Hz input from modern consoles like the PS5 or Xbox Series X.
Position the device so it is measuring the centre of the screen as best you can – the actual sensor is located behind the purple light you can see on the front of the unit, so use that as a guide.
If the screen supports VRR (G-sync or FreeSync) then for PC gaming it is probably best to test with this enabled. Some screens show different performance with VRR turned on and off, so it’s probably best to measure with this on since most people will use this feature.
