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hmscott
07-21-2013, 03:09 AM
The original title is better to Google - LCD Overclocking - as that is the most used wording. You are really changing the refresh rate, or Pixel Clock.

It looks like the panel on my G750 (LCD model: Chi Mei 173HGE) will run clean at 100hz. At 120hz it immediately breaks up in the dark areas, and at 110 it runs an occasional horizontal line glittery - but at 100hz it runs cleanly.

When I saw the Customize button in the Nvidia control panel, I initially tried 120hz, then backed down to 100hz.

The stock 1920x1080 setting also provides 40hz along with the 60hz definition, so I tried that as well. I wonder why they provided 40hz setting? Is there an advantage to underclocking - less power draw? At 40hz dragging around full size Windows seems choppier than 60hz.

I searched in the ROG forums and found nothing on LCD panel overclocking - but google turned up quite a few links about overclocking LCD's from long ago to more recent 2013:

This video seems to cover all the points
http://www.youtube.com/watch?v=8sXeSwe1_dU

Comments? What sync rate is ideal between 60hz and 100hz? Any reason to use a multiple of some other number?

Asus: any issues due to overclocking the LCD drivers, or heat related issues? How about Asus Warranty?

In between tests it's back at 60hz until I confirm with Asus the side effects of running at other than 60hz.

FYI - Using the most recent Asus G750 VGA driver Version V9.18.13.1159 - Nvidia 311.59

Paske
07-21-2013, 06:00 AM
You can not "overclock" an LCD screen.

It is possible to choose custom refresh rate. The GPU will deliver 100 refresh-es in a second, the screen being 60 Hz will refresh 60 times, but will try to do it 100 times in a second. Since that is what driver tells him to do.

As a result you will get a burned out / broken screen and absolutely no picture difference between 60 and 100 Hz.
This was an issue for legacy CRT screens.

There are 100 and 120 Hz screens on market, but they have different panels, electronics, etc. that enables them to work at these speeds.

Far more important for us is wether the panel is TN or IPS.
In depth difference can be found here : http://en.wikipedia.org/wiki/Liquid-crystal_display

Basically - IPS panels have a much better picture quality and view angels then TN panels.

Chi Mei 173HGE - happens to be TN panel , but used in many high grade laptops. Over all quality of the screen is quite good.

hmscott
07-21-2013, 07:39 AM
You can not "overclock" an LCD screen....

Original Title is easier to Google - LCD Overclocking - as that is the most used wording. You are really changing the refresh rate, or Pixel Clock.

The "Overclock" name comes from changing the base/seed clock used to set a microprocessor speed. It used to be a crystal used as the clock reference - usually soldered in place - so you would clip a replacement crystal 'Over' / on top of the stock crystal without unsoldering it - hence - Over the Clock crystal - Overclock.

Perhaps it should have been properly called - Over Crystal :)

Later, we just removed the stock crystal and put in a socket that would accept the clipped legs of a fresh crystal.

Now "Overclocking" has come to mean running something faster than the stock or advertised rate/speed - so I think Overclocking does fit when setting the LCD to run at faster than default refresh rate. And, Overclocking the PIxel Clock seems a bit too obscure for most to recognize what we are refering to, don't you think?

There are enough hits on Overclocking LCD that I think it is a bit late to try to change the common name for running the refresh rate higher than the stock setting.

hmscott
07-21-2013, 07:55 AM
Paske, have you tried increasing the LCD refresh rate yourself to see the difference?

Running a CRT refresh at the top recommended refresh rate provided the best image. Running the refresh higher wasn't usually possible, as the manufacturer worked to tune to the highest speed and sold it based on the specification it could attain. Usually you couldn't run at all much past that refresh rate, it wasn't viewable.

Toward the end of the run of high end CRT's, you could tune lots of parameters, the right ones would let you increase the refresh rate sometimes at the expense of other parameters.

As soon as LCD's came out I tried to run them at higher refresh rates, but never got much more than a few HZ, maybe 65hz at the most before the display wouldn't function. Just like it happened in the video I gave a link to earlier - at 90hz that monitor stopping displaying.

Now, I think the LCD driver components have progressed well beyond 60hz capable, but we haven't been taking advantage of it yet.

I'd like to hear from Asus what they have tried and what they recommend.

Paske
07-21-2013, 08:16 AM
I use to be a salesman for IT and TVs, also use to repair computers. Today my job is still in IT, just on a different level.

Privately I am a gamer and use to spend most of my time as young adult overclocking stuff.

While you can get measurble performance boosts from OC-ing CPU, GPU, RAM, I see no point in overclocking your screen. Other then "because I can" in which case please share your results with rest of us.

Yes LCD-s are capable of 200+ Hz real refreh rates ( not that Plasma 600Hz underlay BS that that nothing to do with real refresh ) , but I have not noticed any difference between 60 and 200 Hz screens when it comes to performance. Also they are / were IPS panels , not TN.

Paske
07-21-2013, 08:42 AM
I read up on LCD overclocking ...

I have not tried it myself, so cant say. But people claim there is a difference . Guess I will have to try and see for myself.

hmscott
07-21-2013, 09:06 AM
The simplest example I can think of is moving a window / dialog in Windows.

At 1920x1080 set up custom refresh rates to 24hz and 100hz (highest in my case) - and switch between those to see the exaggerated difference, way slow next to fastest refresh you can run.

Click on the Title bar of a window - like the Nvidia Control Panel or your browser, and swish it around smoothly - up and down - right to left - and around in a circle, as smoothly and at a speed where you can see it will seem jumpy / jaggy.

Now, it is possible that at over 60hz the LCD in the G750 stops updating any faster than 60hz, even if Windows is pushing more data at a faster refresh rate. But, I think I can see a difference between 60hz and 100hz images.

That is why I have sent a note to Asus to find out the details.

Also, benchmarks at 100hz, all other settings the same, dropped a not insignificant %. Like from 114k to 100k in 3dmark Ice Storm. I am assuming that is due to the larger % of screen updates occurring.

Let us know what you see. To me it images look better, and transitions smoother.


I read up on LCD overclocking ...
I have not tried it myself, so cant say. But people claim there is a difference . Guess I will have to try and see for myself.

hmscott
07-22-2013, 05:47 PM
In the Nvidia Titan release, there is this description for Display Overclocking:

Display Overclocking: Throwing Off The Shackles

Many PC gamers play with VSync enabled to avoid unsightly image tearing that occurs when the frame rate is higher than the monitor’s refresh rate. Most are locked to 60Hz, limiting the max frame rate to 60 frames per second.

Unhappy with this stall in technological advancement, our engineers looked inside today’s LCD and LED-backlit screens, and discovered that many support higher refresh rates. For that reason, we’ve developed Display Overclocking, which allows GeForce GTX TITAN owners to quickly and easily overclock their refresh rates via the same third-party tools that control GPU Boost 2.0. And of course, it works with Adaptive VSync too, allowing games to be played at rates over 60Hz on a “60Hz” screen, without tearing, and without the stuttering associated with normal VSync.

23763

Display Overclocking works with any panel operating at any speed, including the latest 120Hz screens."

http://www.geforce.com/whats-new/articles/introducing-the-geforce-gtx-titan

EpIcSnIpErZ23
07-23-2013, 12:12 AM
In the Nvidia Titan release, there is this description for Display Overclocking:

Display Overclocking: Throwing Off The Shackles

Many PC gamers play with VSync enabled to avoid unsightly image tearing that occurs when the frame rate is higher than the monitor’s refresh rate. Most are locked to 60Hz, limiting the max frame rate to 60 frames per second.

Unhappy with this stall in technological advancement, our engineers looked inside today’s LCD and LED-backlit screens, and discovered that many support higher refresh rates. For that reason, we’ve developed Display Overclocking, which allows GeForce GTX TITAN owners to quickly and easily overclock their refresh rates via the same third-party tools that control GPU Boost 2.0. And of course, it works with Adaptive VSync too, allowing games to be played at rates over 60Hz on a “60Hz” screen, without tearing, and without the stuttering associated with normal VSync.

23763

Display Overclocking works with any panel operating at any speed, including the latest 120Hz screens."

http://www.geforce.com/whats-new/articles/introducing-the-geforce-gtx-titan

Thats very interesting. Let me know the results.

hmscott
07-23-2013, 01:26 AM
Thats very interesting. Let me know the results.

It seems to be working for me at 100Hz. Pretty easy to set up and try a Customized Resolution in the Nvidia Control Panel, and then run with or without vsync enabled on a G750JW-DB71

TX2000
07-23-2013, 01:30 AM
i am running at 100Hz and i used the nvidia control panel
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hmscott
07-23-2013, 01:33 AM
Cool, have you tried a game that runs faster than 60 fps and set / unset vsync in the custom game or global vsync setting?

TX2000
07-23-2013, 01:39 AM
i need some sort of counter on screen to check if it is working. i will check that in a bit

TX2000
07-23-2013, 01:51 AM
here are some screenshots with v sync on and 100Hz
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hmscott
07-23-2013, 02:34 AM
Do you notice any difference running at 100hz, visually improved?

Performance differences to the negative? My 3dmark numbers drop when I increased refresh.

TX2000
07-23-2013, 02:37 AM
from 60Hz i do notice the difference when i force v sync . is more smoother and if i turn it off i get tearing all over the place. i will bench it and post the result after

TX2000
07-23-2013, 02:45 AM
win7 60hz
23837

win7 100hz
23836

the difference is small nothing to blame the refresh rate. anyways 3dmark turns off v sync when benchmarking

hmscott
07-23-2013, 03:27 AM
It was a bigger drop for Ice Storm - from 114k to 100k, when I get time this weekend I will take a look again.

Vsync or not, I think it is pushing a lot more data at 100hz than at 60hz. Perhaps that is why performance drops so much?


win7 60hz
23837

win7 100hz
23836

the difference is small nothing to blame the refresh rate. anyways 3dmark turns off v sync when benchmarking

TX2000
07-23-2013, 03:38 AM
i really don't know about that but i will try to do a full benchmark when i get home . i don't have the OS disks with me to do a reinstall.

roryh86
07-23-2013, 10:54 AM
It was a bigger drop for Ice Storm - from 114k to 100k, when I get time this weekend I will take a look again.

Vsync or not, I think it is pushing a lot more data at 100hz than at 60hz. Perhaps that is why performance drops so much?

Hey hmscott. The refresh rate has nothing to do with performance differences. Your GPU will output as much FPS as it can according to the set screen resolution and the graphic demand of the game/benchmark regardless of what display is connected (internal or external). It won't change its output power and struggle more (so to speak) to keep up with the display, its the opposite, the screen will now be able to catch more frames and display them without tearing (If you're gaming at +60 FPS). If you can enable 100 Hz, then theoretically you should be able to play games up to 100 FPS without tearing, and no need for v-sync.

Also keep in mind that there is pixel response time to pay attention to. At 100 Hz, that is one screen refresh for every 10ms (1000/100). That means your pixel response time has to be less than 10ms to avoid blurring. I dunno what the response time is on the G750, but you wouldn't want to increase refresh rate if its say, a 16ms screen.

roryh86
07-23-2013, 10:59 AM
here are some screenshots with v sync on and 100Hz
23833
23834
23835

TX, you should try disabling v-sync when you have it on 100 Hz and take screen shots, since v-sync is capping frame rate at 60 FPS, so you might as well be @60 Hz. Unless you're getting more than 100 FPS in the game, then even @100 Hz tearing will occur.

hmscott
07-23-2013, 01:10 PM
Hey roryh86, good point about the lcd response, we could start pushing into that limit. I don't see blurring yet.

vsync at 100hz means the same as vsync at 60hz, just at a higher refresh/fps rate.


Hey hmscott. The refresh rate has nothing to do with performance differences. Your GPU will output as much FPS as it can according to the set screen resolution and the graphic demand of the game/benchmark regardless of what display is connected (internal or external). It won't change its output power and struggle more (so to speak) to keep up with the display, its the opposite, the screen will now be able to catch more frames and display them without tearing (If you're gaming at +60 FPS). If you can enable 100 Hz, then theoretically you should be able to play games up to 100 FPS without tearing, and no need for v-sync.

Also keep in mind that there is pixel response time to pay attention to. At 100 Hz, that is one screen refresh for every 10ms (1000/100). That means your pixel response time has to be less than 10ms to avoid blurring. I dunno what the response time is on the G750, but you wouldn't want to increase refresh rate if its say, a 16ms screen.

hmscott
07-23-2013, 02:33 PM
After exchanging a few emails with Asus, they came back with these answers to my questions, edited, questions follow.

Answers:

Thank you for contacting ASUS Customer Service.
My name is XXXX and it is my pleasure to help you with your problem.

For the first question, it is OK to set the rate at 60-100hz.

For the second one, it won't be negative for your laptop. Actually, you can choose any rate among 60-100hz.

For the third one, the refresh rate of 85 means the image is refreshed 85 times in a second.

Questions:

1) I would still like to know if it is ok to set the refresh rate at 85hz, 90hz, or 100hz, as
the image display and the motion in graphics programs improves.

2) Is there anything negative about doing it? Will it generate too much heat in
components, etc. I realize the default setting is 60hz, but since it is possible to set
higher, and it looks better, I would like to set it higher than 60hz. I also realize this
isn't a 120hz supporting panel, but it works up to 100hz.

3) Will the LCD panel electronics update the LCD faster than 60hz. If I set it to 85hz
is it updating 15 times more per second than at 60hz?

If you can forward this on to an engineer familiar with the design / operation I will be
happy to wait for the answer. If you are that person, please let me know.

TX2000
07-23-2013, 09:56 PM
TX, you should try disabling v-sync when you have it on 100 Hz and take screen shots, since v-sync is capping frame rate at 60 FPS, so you might as well be @60 Hz. Unless you're getting more than 100 FPS in the game, then even @100 Hz tearing will occur. when i disable vsyng and i am running at 100Hz it will jump to like 150 something fps. that game let you select 60 and 100Hz vsync

hmscott
07-25-2013, 11:38 AM
TX2000, can you please try changing to 85hz and see if the game tracks the change, offering 85hz/60hz instead? It is odd that 100hz is there if not due to your current refresh rate.

TX2000
07-25-2013, 07:47 PM
TX2000, can you please try changing to 85hz and see if the game tracks the change, offering 85hz/60hz instead? It is odd that 100hz is there if not due to your current refresh rate.


i will try to do that later i am not at home right now

TX2000
07-26-2013, 03:22 PM
here are some pictures at 85Hz. i changed the refresh to 85 and now the 100HZ option dissapeared
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hmscott
07-26-2013, 03:43 PM
here are some pictures at 85Hz. i changed the refresh to 85 and now the 100HZ option dissapeared


Cool, that looks good. It will vsync at your refresh rate. Question is, is there a reason to not set vsync when refresh is at 100hz or greater? Is there a noticeable difference in gameplay if vsync is OFF and you are rendering > 100 FPS?

The extra frame generation is going to cause CPU/GPU resources to be used at a higher rate, generating heat, but not doing much more in the way of improved visuals?

Thanks TX2000!

TX2000
07-26-2013, 03:47 PM
Cool, that looks good. It will vsync at your refresh rate. Question is, is there a reason to not set vsync when refresh is at 100hz or greater? Is there a noticeable difference in gameplay if vsync is OFF and you are rendering > 100 FPS?

The extra frame generation is going to cause CPU/GPU resources to be used at a higher rate, generating heat, but not doing much more in the way of improved visuals?

Thanks TX2000!

without Vsync on some games render 100+ frames and you get tearing on your screen. in that game i can hit 150+ fps. Also i tried 110 and
120Hz . at 120Hz the screen got glitchy so i dialed back to 100. I think 100 is the sweet spot.