fazeobama wrote: ā23 Nov 2021, 23:09
Hello my friend, I own the same model monitor as you and have been overclocking the refresh rate to exceed 144hz for roughly a year and a half now. However, I have never managed to break past 211hz on my xl2411p. I'm curious, how in the world did you manage to achieve such a high refresh rate on this 144hz monitor?!?
If you don't mind, could you please share a screen grab of what particular settings you used in order to reach 283hz? I would very much so highly appreciate it.
Thanks!
Hey, I haven't checked here in a while, sorry for the late response. My monitor is the 2420te (144hz revision), so not the exact same as the xl2411p. I was replying to him assuming that perhaps some of the same things apply for more of the 144hz models, which might or might not be correct. It will probably depend on whether the monitors' implementation of "instant mode" & their scalers behave similarly, as these seem to be the two biggest factors in overclocking this monitor (my scaler is MST 8556t according to the service menu, supposedly the xl2411p also has this same scaler too according to a random picture on google images).
Because I have the S-switch, it is a lot easier to try different settings and I was able to essentially brute-force a lot of the quirks out of this monitor. However I haven't messed with it in a while and my memory might not be perfect regarding a few details, but I'll try to remember the most I can. A tl;dr first in case you want a quicker answer that might solve your problem:
If you are "capped" at 210hz, even in lower resolutions, the most likely reason is that you are not actually making video scaled resolutions but rather GPU scaled resolutions, which are still 1920x1080 and will abide by its limits. So:
- To go over 210hz you must use a lower video scaled resolution, no way around it as you are hitting the maximum pixel clock (~480MHz) if you use 1920x1080p@210hz. I have heard Windows10 makes it more difficult to use real display scaling, so perhaps a lot of people do not even realize they are running gpu scaled resolutions unless they check the monitor's OSD(edit: I forgot you can also change some color settings to allow slightly higher bandwidth through the cable as well).
- To avoid glitched resolutions and improve your rate of success, it is generally better to be in the desired resolution prior to switching to the OCed version of it, especially if the vertical values do not match. So for example if you wanted to make a 1350x1080@240hz (5:4) resolution, it is preferred to be at its non-OCed version before switching to it and also on the same scaling/display mode. (must make sure it is also video scaled and not GPU scaled, otherwise it will be pointless to do this)
- If your desired aspect ratio does not match the best OC you are able to achieve, through nvidia's custom resolution you are able to scale it back/up to any fake resolution with any aspect ratio you may wish (will not look great to say the least, but it works and appears not to add additional input lag, on my setup anyway).
Achieving very high OCs
First figure out what the limiting factors are and work from there, then search for possible "magical values" that may work better than others. As an example, in my monitor's case (*instant mode ON, display mode "Full"):
- Max Pixel Clock: ~330MHz
- Max Horizontal Resolution: values below 1400, roughly (screen looks glitchy & frameskips above this value)
- Vertical Resolution (active pixels): very important, the monitor can be very picky here; generally deals better with the native value, possibly because the resolution I'm using prior to switching to an OC matches it and therefore it handles it better (so either 1080p or the same value as the resolution prior to switching to its OCed version). Messing with this value is what allowed me to achieve my highest OC; by using 1280 active pixels as the vertical resolution, the monitor is able to go as high as 281hz-286hz (windows and OSD show distinct values) without glitching out. I don't know why this value in specific, but it must have something to do with the scaler.
Additional information that might be useful:
- Instant mode OFF: this majorly affects the way the OC behaves, at least on this monitor. With instant mode OFF, the OC behaves in a much more predictable manner, without any major glitches and abiding by the expected ~480MHz pixel clock limit which translates to about 210hz at 1920x1080p resolution, which I assume is the limit you are hitting on yours. The monitor can do up to 255hz with instant mode off on lower resolutions, with higher values wrapping around and resulting in "frameskipped" versions of their equivalent refresh rates (i.e 500hz is actually something like 240hz but frameskipped).
- Instant mode ON: with it ON, the OC behaves much less predictably. At first it made me think I could not overclock this model at all as anything over 150hz resulted in a severely glitched screen, regardless of the pixel clock or any other parameter. I discovered however that only the 150hz-200hz range seemed to be bugged in this manner, values higher than 200hz displayed normally, with just some slight screen offset. On this mode however, the pixel clock "limit" changes for some reason, to around ~330MHz. The max "usable" refresh rate becomes about ~262-267hz, with higher values working without frameskipping (even as high as 500hz, and very likely even higher), but displaying in very very glitched ways which are absolutely unusable.
- Built in scaling modes: shockingly, instant mode appears not to function at all in any of the "display modes" except of "Full", regardless of it being enabled or disabled in the settings. I assume so because in any of the other modes the OC behaves the exact same as it does with instant mode OFF and the input lag is also obviously noticeable. It was well known at the time of the release of these monitors that the scaling modes seemed "off" and nobody seemed to play with them. It was thought that the scaling itself was perhaps a laggy implementation, but I guess it was just the fact that instant mode is either bugged or incompatible with these modes for technical reasons. Still very misleading to show it is "on" even though it is not.
- The profile, scaling modes and resolution you are in BEFORE you do the OC trick matter and majorly affect how the OC behaves and its success and/or failure. It is something that should be paid major attention to. For the people using the software to trigger the OC & switch profiles I'm not exactly sure what could be the implications as I have never tested it.(assumption: the monitor does not properly switch all of its internal parameters adequately since it never finishes applying the resolution in a regular way, so some settings "carry over" from the last mode/resolution)
- If you set the back porch to 0, the screen gets divided in two with each half updating alternatively to each other (useless but interesting to look at)
- You can also get a bugged interlaced OCed mode working by using HDMI cable, which is obviously not real interlaced, but might be useful in some way depending on the vertical values the monitor works better with. I remember very little of this but it was interesting to see it even worked at all.
- VGA displays different resolution values than the other cables in the OSD when using "bugged"/OCed resolutions, perhaps offering a hint of what is going on internally with the scaler during the OC.
The least glitchy looking 500hz I managed to get working if anyone wants to try. No frameskipping. Highest hz is unknown as win7 limits me to 500hz. The mouse feels amazing even though it is so tiny and difficult to use!
Highest fullscreen "usable" OC. Looks pretty bad but no frameskipping. Also works with 1440 vertical active pixels. Because i'm limited to 330MHz I need to use terrible horizontal values to keep the pixel clock in range; other monitors might not have this issue.
That is all of the relevant information I can remember for now, I might edit it later.
The most relevant finding out of all of this is the issue regarding instant mode not working in most display modes and the maximum pixel clock differing from on and off values. It makes me wonder whether this is an isolated issue/bug/limitation with the very old benqs or if it is also true for any newer models too. If it true for newer models too it is possible that the overclocks people are achieving here are actually with instant mode OFF rather than on and would be pointless because if you have it disabled the monitor has much higher input lag and is essentially unusable. I imagine it is not the case, but it is worth investigating for sure.