Overclocking your LCD panels?

Discussion in 'Overclocking, Benching & Modding' started by mkk, Jul 3, 2013.

  1. mkk

    mkk Well-Known Member

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    Something I've tried in the past with programs like Powerstrip but forgot about for a couple of years, but now tried again thanks to an easier piece of software called Custom Resolution Utility. Apparently people use it with varying goals in mind but I thought simply raising the refresh frequency a little bit above the regular 60Hz might be a good enough reason. Back in the days of playing Quake 3 on CRT screens I developed a keen eye for differences in frequency, so a 20% boost from 60 to 72Hz is noticeable.

    Reaching around 72Hz seems to be fairly common with many of todays 1920x1080 monitors, but results may vary. Also as is the case with the VA-panel based monitor that I have, increased refresh rates does not affect the pixel response itself, as pixels will remain as slow as they were to make certain color shifts or going to and from pure black to white. So more straightforward gains should be with basic TN panel screens. LED backlighted screens are probably also best, for the simple reason that they don't run as hot and heat might be a limiting factor for the monitors refresh rate control chip.

    Some games don't care what refresh rates are enabled in Windows and just run at 60 anyway, but I've had success with most so far.

    Sample shot of the program with my current settings. The field Detailed resolutions is key and the only place I had to do something. I tried 66Hz first and left it in place in case 72 would act up. Also leave a 60Hz still in there or some games might crash on startup. I recommend trying the timings at Automatic - LCD Reduced when adding new resolution modes.

    [​IMG]

    Original software thread on the creators forum with (brief) instructions: http://www.monitortests.com/forum/Thread-Custom-Resolution-Utility-CRU
    This method supposedly only work with AMD and Nvidia graphics so far.

    Edit: After noticing that the idle clocks of my graphics card (HD7950) were much increased when running at 72Hz I tried other frequencies and settled for 70Hz. I haven't measured the difference with a watt meter but it's probably fairly significant, if you value low load power consumption at all that is.
     
    Last edited: Jul 7, 2013
  2. Judas

    Judas Obvious Closet Brony Pony

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    yeah overclocking ones monitor kinda comes and goes.

    What I've found is that if you aren't careful, even if you manage to get a stable oc at lets say 72hz over the 60hz standard, it can SERIOUSLY reduce the lifespan of the panel simply due to the chips running hotter than they should, and or operating at frequencies that it wasn't necessarily designed for.

    I've actually a panel here that was operated at 90hz for about 2 months before it went berserk. It's ceiling was 96hz at which point any setting above and the "OUT OF RANGE" message would appear.

    The screen still mostly works, but randomly without reason, irregardless of temperature or humidity or signal being received, it'll just go into a panic of lines/flashes/solids/garbled images.

    Initially I thought it was just a bad monitor, but the customer went and bought another.... 2-3 months again same issue.

    His 3rd monitor that he bought he figured he'd run at only 85hz... and I haven't had a call back since.

    So I've had actually 2 of the same model monitor that exhibit the same symptoms. One I sold for essentially nothing for the singular purpose of being a secondary monitor that would be rarely used... the other still remains.

    Another case with identical symptoms is a netbook that also somehow managed to have it's lcd panel overclocked from 60hz to 75hz.... worked great until one day...... same thing started happening.
     
  3. Dyre Straits

    Dyre Straits 10 Grandkids -2 Great-grandsons

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    Since you're talking about screen Hz, how well do AMD and nVidia cards handle the screens that come with 120Hz already?

    I ask this because I picked up a 40-in LCD a couple nights ago that is 120Hz out of the box. But, CCC sees the maximum as 75Hz. Would using the LCD Overdrive in CCC work for boosting the Hz to the default?
     
  4. mkk

    mkk Well-Known Member

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    If it is truly capable of 120Hz input rather than being one of the usual screens in that size that simply shows the same image for more than one frame, then you should be good if you can get a driver for that screen installed in Windows. Check the manufacturers website if there was no driver disc coming with the screen. If it's a true 120Hz-input screen then there must be a driver available for it or it wouldn't normally do it's thing for anyone. The cable also has to be either a Dual-link DVI, DisplayPort or a HDMI v1.4b or later with support at both ends.
     
  5. Judas

    Judas Obvious Closet Brony Pony

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    Most tvs are advertised as 120hz LCD..... but it's the panel NOT the input frequency...

    Basically it's kinda of a half truth.

    True 120hz input displays are still rather expensive.

    DVI-D or Display port or HDMI connected 120hz panels handle it quite well. Also display port seems to be tuned for it best.
     
  6. Dyre Straits

    Dyre Straits 10 Grandkids -2 Great-grandsons

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    Being that this is actually a HDTV and not a monitor, I believe drivers won't be located other than the Generic drivers that get loaded when it gets detected by Windows.

    Other than the quick pop-up info that shows up when the signal changes, how would one test the actual Hz rate? And, yes, I found in the manual that it's the PANEL that's 120Hz. So, that pretty much rules out increasing the input frequency, correct?

    Checking the FAQ at SEIKI Support I find this: All signals going into the TV are at 60Hz, but the TV UPSCALES the frequency to 120Hz.
     
    Last edited: Jul 6, 2013
  7. Judas

    Judas Obvious Closet Brony Pony

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    on the seiki... people use programs as what has already been suggested to keep ramping up the output frequency from the video card to the tv.... when the output frequency triggers the out of range cut off (where the chip just basically stops responding entirely) then you know your ceiling...
     
  8. Dyre Straits

    Dyre Straits 10 Grandkids -2 Great-grandsons

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    If I'm understanding the situation correctly, due to how the SEIKI engine upscales the 60Hz to 120Hz, does that mean that any increase in frequency that I would generate, would, in turn be doubled by the engine? Such as, if I were able to increase frequency to 75Hz -- which is what CCC detects -- does that mean the engine would be upscaling to 150Hz?
     
  9. mkk

    mkk Well-Known Member

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    It's a good question but I'd suspect it might just try to upsample anything to 120Hz, as a TV set often has to deal with signals other than 60Hz it can't just double anything if it's supposed to run at 120Hz as a main feature. Checkin the specifications for that specific model might give some insight. Just maybe there could also be some information tool that show the current frequencies in its on-screen menus?

    Try 75Hz and see if for instance the updates of dragging windows around appear any smoother.
     
  10. Dyre Straits

    Dyre Straits 10 Grandkids -2 Great-grandsons

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    It does make sense that the TV engine may attempt to even out the refresh rate. So far, though, I'm not that excited about trying to increase what already looks to be very good performance.

    We'll see how it goes.
     
  11. Judas

    Judas Obvious Closet Brony Pony

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    the few people that have that seiki 4k tv.... when running 192hz output to it's input @ 720p (1280x720) I'm not sure what tool they were using (apparently a LOT of professionals have been going over the sucker with a fine tooth comb who specialize in monitors/displays/etc.) Stated that the input of 192hz and the resulting display frequency actually matched.

    Generally though. With a 60hz input for the components, the panel can be 120hz. Usually the panel will remain the same and only the input frequency can increase. But maybe it's possible for 120hz lcd panel to make it 1:1 when you hit 120hz.. and then increase to a higher frequency if the input frequency exceeds it's own. So 60 - 120 the panel frequency stays the same maybe... then 121+ the input and panel frequency increase as they are in sync.

    All I know is.... That i'm waiting for the first video cards with proper HDMI 2.0 outputs (which allows 4k display output at 60+hz) to arrive. At which point we'll see if that seiki tv is actually HDMI 2.0 compliant meaning that we won't be stuck as 30hz progressive.
     
  12. Dyre Straits

    Dyre Straits 10 Grandkids -2 Great-grandsons

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    I may should start a new thread about this, but, since it's still about my SEIKI somewhat, I'll put it here:

    I notice that when I clone my main Viewsonic and the SEIKI ... with them being the only monitors active at the time ... I'm getting some noticeable tearing on my Viewsonic. The "tear line" is about 1/3 of the way up from the bottom of the screen. I don't see it happening on the SEIKI, though. And, if I disable the clone the Viewsonic returns to normal.

    EDIT: It appears that, according to Microsoft, this tearing is unavoidable under these circumstances....

    http://support.microsoft.com/kb/972194
     
    Last edited: Jul 11, 2013
  13. Judas

    Judas Obvious Closet Brony Pony

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    swap your connection around if you can...

    I know that on any monitor that I put display port on... it's tear free.
     
  14. Dyre Straits

    Dyre Straits 10 Grandkids -2 Great-grandsons

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    I had to jump through several hoops to get the HDTV and the DP-connected display to work properly...for some odd reason.

    When I first attempted to simply duplicate/clone the desktop on the two, the DP display wanted to only come up at 640x480...but with actually no image on the screen.

    After several other attempted configurations, I finally had to pull the Mini-DP plug and plug it into the port at the far end of the video card.

    So, I finally got cloned desktops on both the HDTV and the DP-connected display at the moment.

    The tearing, indeed, is absent on the DP-connected display but very apparent on the HDTV...in the same position as I mentioned above.
     

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