Display "overclocking"

[|Omicron|]

Today I stumbled on this trend of driving displays at more than their rated refresh rates, particularly linked to IPS displays of Korean manufacturers like Yamakasi etc. This kind of surprised me, because I've always lived under the assumption that LCDs can only be driven at specific fixed refresh rates.

Now I have the following questions:
- How does one go about doing this in the first place?
- Can you actually damage the monitor by doing this?
- Does it only work with these Korea-manufactured displays because they don't bother disabling it, or can any LCD technically be driven at more than its rated refresh rate?
- And of course: does it influence the picture quality or performance of the display in any way?

 

[XoR]

higher refresh rate is supported by some displays that use simple electronic. Most common limit is 75-77Hz at 1920x1080

it is helpful in games to reduce input lag and tearing (when v-sync is off). Also setting monitor to multiply of 23.976Hz (eg. 71.928Hz) reduces stuttering in movies.

 

[kalston]

- How does one go about doing this in the first place?
By creating custom resolutions in the video drivers and/or modifying the EDID (which tells the OS what the display is capable of).

- Can you actually damage the monitor by doing this?
As of yet no one seems to have damaged his monitor by doing so. Some monitors become noisy when you do, or show weird lines or some corruption, but reverting to a lower refresh rate always seems to be enough to fix it. No permanent damage has been reported. Some of us (like ToastyX or myself) have been running overclocked LCDs for years without any issue.

- Does it only work with these Korea-manufactured displays because they don't bother disabling it, or can any LCD technically be driven at more than its rated refresh rate?
No, plenty of LCDs can be overclocked. Some better than others. It's hard to tell what makes it possible/impossible but my personal experience is that high end displays often have strict electronics that prevent overclocking while cheaper displays often let you do it without too much trouble (but some of them let you do it while skipping frames, resulting in a terrible experience).

- And of course: does it influence the picture quality or performance of the display in any way?
Picture quality certainly not (unless it is NOT working fine), performance certainly yes (75hz vs 60hz is already pretty noticeable for many, 100-120hz (Korean monitors) is noticeable for even more people). It matters a lot for gaming and video playback (as mentioned by the above poster).

 

[Mr.Pixel]

- And of course: does it influence the picture quality or performance of the display in any way?

If a display uses overdrive, then overclocking it may cause the overdrive to increase the response time. See example here. Displays without overdrive would of course be unaffected.

 

[|Omicron|]

Hmmm. Interesting!

Since I may or may not have to invest in a new monitor later this year (my 6 year old venerable Samsung is starting to show bad backlight flicker and uniformity issues when switching on, though they disappear during the first 30 seconds... so far) this is valuable info. For starters, I love to tinker and try things for the heck of it. Though permanently driving my display at 75Hz-90Hz might be fun if I notice a quality of life improvement through it.

I'm wondering though... many games for example don't support custom resolutions properly. Would I end up running into cases where some applications give me 75Hz and others don't? Or does editing the EDID provide a catch-all method?

 

[kalston]

If you edit the EDID (or rather do an "EDID override" which is perfectly safe and easy to revert back from in case of issues) I can't think of any game that won't accept those custom resolutions. However if you only make custom resolutions through the GPU drivers you'll have a lot of problems, especially on Win 7 (on XP most of my games seemed to prefer the desktop mode without doing anything special)

 

[Mr.Pixel]

Would I end up running into cases where some applications give me 75Hz and others don't?

Some games are locked to 60fps or lower. Some like to force the 60fps option if available, so the 60fps option must be removed from the EDID. A short list of games is here, and there are several discussions on that site about how to get them working.

 

[JaXter]

I`m very curious have there been results of people trying to overlock the S23A700D a 120hz screen to something even higher, is that even possible?