Member Avatar for JordiB

I know that refresh rates are not supposed to apply to LCD monitors, but there is still an setting that allows me to set it in Windows' options. This setting does seem to have some effect, but since LCD's don't really refresh, I am wondering what the setting is doing. Is it perhaps adjusting the rate at which my computer is sending update information to the display? If so, why can't I just set it to really high (i.e. higher than 75Hz)? My computer should be powerful enough to send update information a lot faster.

Also, I was wondering about the relation between 'refresh rate' and response time. I have one LCD monitor with a response time of 25ms, which means (I think) that it should only be able to update at 40Hz, but for this monitor the listed refresh rates are also 60 and 75Hz. What happens to the displayed image when the refresh rate is higher than what the response time suggests that the monitor is capable of?

Thanks for your time!

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  • Latest Post Latest Post by Xlphos

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Short answer for : the Windows “refresh rate” setting controls the vertical timing the graphics card outputs and the rate the monitor’s electronics use to present new frames. LCD panels don’t scan with an electron beam like CRTs, but they still receive and display frames at a vertical frequency. The OS normally shows only modes the monitor reports as supported (EDID), so selecting an arbitrarily higher Hz is blocked by the panel’s scaler, the panel’s pixel-clock/bandwidth limits and the cable/interface.

How refresh rate and response time relate: response time (usually quoted in milliseconds, often gray‑to‑gray) is the time a pixel takes to change state. A 25 ms pixel transition does not forbid 60 Hz or 75 Hz modes — it simply means pixels may not reach their final value before the next frame arrives. The visible result is smear or trailing rather than a failure to display the frames. That’s why a monitor can advertise 60/75 Hz yet still look ghosted if its pixel switching is slow.

Practical points and causes of confusion: manufacturer response‑time numbers are best‑case and measured under specific transitions, so real scenes often look worse. “Overdrive” in many monitors speeds transitions but can cause overshoot (inverse ghosting). Interface/cable bandwidth also matters: higher refresh at a high resolution needs more pixel clock; some connectors or single‑link modes won’t support those timings. As noted, the GPU can produce many frames per second, but the displayed result is limited by the monitor’s chosen timing unless vertical sync/variable‑refresh technologies are used.

Quick troubleshooting checklist:

  • Verify the monitor’s on‑screen display for the active refresh rate and compare with Windows’ setting.
  • Use the monitor’s native resolution and a digital cable (DVI/DP/HDMI) for higher Hz.
  • Try the monitor’s overdrive setting if motion blur is the issue, and watch for overshoot.
  • Consult the monitor manual/EDID for the supported modes before forcing custom timings.
Member Avatar for Xlphos

Hello

Just to let you know I believe refresh rates do apply to LCD monitors.

It's not how fast your computer can generate the picture it is what the monitor can handle and what is worthwhile; meaning can the human eye tell the difference.

The response rate is how fast a monitor can react to change, the screen is refreshed regardless of any changes made.

Your computer graphics card will generate frames. These frames may add upto 100 Frames Per Second but if the monitor is operating at 50 hz only 50 frames would be displayed.

Check out Fraps this will tell you how many frames are being generated.

- Hope this explains some.

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