Monitor Tests Forum

Hello guys,

first of all i have to thank all of you guys, you realy helped me setting up my monitor for perfect play experience!

My question is, what is the maximum pixel clock my monitor can handle and do i have to patch it.

I have a ATI R9 280X and a BenQ XL 2430T connected over displayport. When i set up my resolution at 144hz, the monitor cant display it. At 120hz its fine. And i havent touched the vertical total value, i dont know what it realy does.
When i set up at 1440x1080 with 120hz and a vertical total at 1500 the pixel clock gets around 396mhz. I never tried that, because i am afraid of breaking my monitor.

Can you help me with this?

Regards
Freasy

(10-01-2015 06:29 AM)Freasy Wrote: [ -> ]Hello guys,

first of all i have to thank all of you guys, you realy helped me setting up my monitor for perfect play experience!

My question is, what is the maximum pixel clock my monitor can handle and do i have to patch it.

I have a ATI R9 280X and a BenQ XL 2430T connected over displayport. When i set up my resolution at 144hz, the monitor cant display it. At 120hz its fine. And i havent touched the vertical total value, i dont know what it realy does.
When i set up at 1440x1080 with 120hz and a vertical total at 1500 the pixel clock gets around 396mhz. I never tried that, because i am afraid of breaking my monitor.

Can you help me with this?

Regards
Freasy

You can't create a 1440x1080 144hz display scaled resolution.
If you need to use 1440x1080@144hz, use GPU scaling and it will use the 1920x1080 resolution.

Create a 1440x1080 60hz lcd standard resolution then use GPU scaling.

You also can't use vertical total tweaks at 144hz at all. 144hz requires "reduced vertical blank"; this is about vertical total of 1098. Going much higher will cause a black screen out of range. *EVERY* monitor is like this, except a few Korean monitors that CAN use normal timings at 144hz and possibly the upcoming 200hz monitors, but video cards will still need to support those.

Also if your pixel clock is 396 MHz, that's too high. The Mstar scaler will show image corruption because it's operating outside of parameters.

For 120hz: Vertical total 1500, and also for 100hz vertical 1500, use these timings.

1920x1080 @ 100 and 120hz:

Front porch: 48 pixels, 3 lines (you probably have this at 88,4).
Sync width: 32 pixels, 5 lines (you probably have this at 44, 5).

Horizontal total: 2080 (you probably have this at 2200).
vertical total 1500.

You can use this for 100hz and 120hz. You can even use it for 125hz!
The pixel clock should be 374.40 MHz at 120hz with these timings, and 312.00 MHz at 100hz.

If you want to use 1440x1080, and want to use a vertical total tweak, create a 1440x1080 60hz resolution in ToastyX CRU. Use LCD standard timings for it. Delete your 1440x1080@120hz or 100hz one you made. then enable GPU scaling in the drivers.

Then when you select 100, or 120hz at 1440x1080, it will use the 1920x1080 with VT tweak applied, downscaled to 1440x1080 on the videocard. If you want a 1:1 image with black bars, select 1:1 in the VIDEO CARD PANEL. Do not select it in the monitor! The monitor scaling options become distorted and act strange when using vertical total tweaks.

If you want 1440x1080@144hz, this will be gpu scaled from 1920x1080@144. remember 144hz can NOT use VT tweaks at all ! (default VT for 144hz=1098, LCD REDUCED TIMINGS).

The absolute maximum pixel clock the Mstar scaler can handle without severe image corruption is somewhere between 430-440 mhz.
The DVI limit is based on that and your dvi cable assuming the pixel clock patch is applied.

For displayport the absolute limit is 480 MHz for 6 bit and 360 MHz for 8 bit. But the scaler can't seem to do more than 440 MHz without corruption.

I was able to use the VT 1500 "trick" to create a 2560x1440 110 MHz custom display scaled resolution with a 440 MHz pixel clock. (reduced HT of 2656).

Hello,

and thanks for the awesome answer, i need some time to understand all of it ;-).
But one thing i can say now, i cant enable gpu scaling, that produces input lag and thats no option for me.

I am working at 1440x1080@120hz atm. and its great for me, but i want to increase the pixel clock. So i will just try to understand your post und and try to increase vertical total and decrease horizontal total i guess to get a pixel clock around 400mhz@120hz, or maybe 125hz since my polling rate of my mouse is 500hz i think i can sync that up better, but thats a other topic.

Thanks for your detailed answer!

Regards
Freasy

(10-04-2015 09:16 AM)Freasy Wrote: [ -> ]Hello,

and thanks for the awesome answer, i need some time to understand all of it ;-).
But one thing i can say now, i cant enable gpu scaling, that produces input lag and thats no option for me.

I am working at 1440x1080@120hz atm. and its great for me, but i want to increase the pixel clock. So i will just try to understand your post und and try to increase vertical total and decrease horizontal total i guess to get a pixel clock around 400mhz@120hz, or maybe 125hz since my polling rate of my mouse is 500hz i think i can sync that up better, but thats a other topic.

Thanks for your detailed answer!

Regards
Freasy

Ok,
You CAN use 1440x1080@120hz with DISPLAY scaling and a custom resolution and get 1:1 pixels (meaning : black bars left and right but full size above and below). Due to the scaler limits, you cant do it at 100hz because of things I can't explain (well you "can" but it will mess up the strobing, LONG LONG story).

For 1440x1080@120hz display scaled, use these exact settings:

front porch 88 pixels 4 lines
sync width 44 pixels 5 lines
Horizontal total: 1720
vertical total: 1125.

Note the default VT is 1144. using this will stop 1:1 and aspect from working in the OSD, because the scaler will see that native vertical resolution is used and disable the 1:1 and aspect settings making only full screen 1440x1080 available. By using a VT of 1125, the scaler will use an internal resolution of 1400x1050 (don't ask how I know this) which is less than 1080, and thus unlock the 1:1 and aspect settings in the OSD. Note the OSD will still report 1440x1080. The Scaler will report 1400x1050. The scaler resolution is shown in the FACTORY menu, not the service menu. (at least in V3+ firmware on xl2720z and xl2420z and xl2411z).

Also strobing will work correctly with these settings and will not strobe out of sync.

however using 100hz display scaled is a problem. The default VT for 100hz is 1133. This will work but again only fullscreen will be available.

However due to scaler issues, reducing the vertical total to unlock the 1:1 and aspect settings in the OSD (like going from 1133 to 1114) wil unlock the settings but the scaler will think it's running at a 120hz refresh rate and will strobe strangely (it will act like it's double strobing or trying to strobe at 120hz sync, and will keep acting like this until the "Strobe Phase " (in the service menu) or "Area" equivalent of strobe phase in the OSD: is raised to around 40-50'ish. There is no workaround for this at 100hz. Using 1125 vertical total at 100hz (which will still strobe correctly) will still not unlock the 1:1 and aspect settings.


So anyway if you use the settings I mentioned and use 120hz, you can use display scaling and gain full screen, 1:1 and aspect control through the OSD of the monitor.

Hey again,

thanks for the fast answer, i havent understood your previous answer and you came up with another i dont fully understand.

But thanks! I did your settings, and i have 1440x1080@120hz strechted with display scaling exact the thing i wanted. So thank you!

The pixel clock is at 232mhz and i cant get it higher right? Because i want 1440x1080?

As far as i think i undestood this whole magic is that the faster the pixel clock is, the less is the input lag and display response time? Am i mistaken?

The whole topic of vertical total, porch, pixel clock and so on is realy interesing and i would like to understand it at the fullest, but dont bother when the questions i ask arent worth answering.

Regards
Freasy

(10-04-2015 05:28 PM)Freasy Wrote: [ -> ]Hey again,

thanks for the fast answer, i havent understood your previous answer and you came up with another i dont fully understand.

But thanks! I did your settings, and i have 1440x1080@120hz strechted with display scaling exact the thing i wanted. So thank you!

The pixel clock is at 232mhz and i cant get it higher right? Because i want 1440x1080?

As far as i think i undestood this whole magic is that the faster the pixel clock is, the less is the input lag and display response time? Am i mistaken?

The whole topic of vertical total, porch, pixel clock and so on is realy interesing and i would like to understand it at the fullest, but dont bother when the questions i ask arent worth answering.

Regards
Freasy

Input lag is based on around 6 overall things:

1) scaling/display scaling, gpu scaling, bad NVidia drivers adding more input lag with GPU scaling, and so on.

About display scaling and the Benq OSD scaling settings: (the "full screen" option in the monitor OSD has no extra input lag added for display scaled resolutions. it seems that 1:1 and aspect have at least a frame added but this COULD be placebo, as the entire screen is smaller (black bars) at 1440x1080 with 1:1, so it could be eye tricks.

2) current refresh rate: input lag is based on framerate+refresh rate (assuming vertical sync is on) equal to 1000 divided by refresh rate in milliseconds (e.g. 1000 / 120=8.3)=8.3 miliseconds for 120hz.

3) The strobe phase setting in the monitor when blur reduction is active: Strobe phase at 100 has 1 frame lower input lag while strobe phase 000 has 1 frame HIGHER input lag; example, at 120hz refresh rate, strobe phase=000 has 8.3ms higher input lag than strobe phase 100 when using blur reduction. But strobe phase 000 has less crosstalk on bottom of screen than strobe phase 100. NOTE: Using a VT tweak limits the maximum strobe phase allowed before the backlight shuts off. The 1 frame higher/lower rule still applies the same way, except the limit drops from 100 to between 47-59. So if using blur reduction, use the max strobe phase possible as long as the brightness through strobe "Duty" is high enough.
(XL2430t: strobe phase=AREA, strobe duty=INTENSITY).


4) video card interactions with anti-aliasing; using high levels of antialiasing with vertical sync can cause extremely high levels of input lag at very low framerates. Example: using something like 4x Supersampling AA @ 60hz refresh rate @ 60 fps may cause 300ms of input lag. I do NOT know why. Maybe ToastyX knows why. I do know that in some games, like Unreal Tournament 2004, there was an ini tweak called "ReduceMouseLag=true" which would remove extra input lag caused by stuff like this, but would decrease maximum framerate.

5) mouse polling rate input lag: 125hz =1000/125 = 8ms, 250hz=1000/250=4ms, 500hz=1000/500=2ms, and 1000hz:1000/1000=1ms.

6) For directX 9 and older games: The "max frames allowed/ Prerender Limit" setting for Nvidia GPUs and the "FlipQueueSize" setting for AMD cards. Prerender Limit / Flip Queue Size=1 have lowest input lag (but some games may stutter with this; the default is "3"). Prerender Limit / Flip Queue Size is IGNORED if vsync is off. This is a vsync on only setting. In windows XP, you could use a value of "0" for super low input lag. This was removed and now "1" is the lowest value for windows 7+.

I think that "ReduceMouseLag=TRUE" in Unreal Tournament 2004's INI file sets prerender limit to 0 through the game engine.

The monitor "Pixel clock" has NOTHING to do with input lag.(toastyX: if im wrong please correct me).. But the higher the refresh rate, the higher the pixel clock needed for the refresh rate....and the higher the refresh rate the lower the input lag.