1680x1050@75Hz

[Roobir]

I searched a bit through the internet and came across some interesting information. Eventually I successfully made a custom resolution to run at 1680x1050@75Hz.

It displays on my Samsung 2232GW onscreen menu as 75Hz and with vertical sync it caps at 75fps.

Here are the timings I used:

I have also done this with a ATi HD4890 using powerstrip in Windows 7 x64.

Can anyone tell me what the consequences are for forcing this and why I cannot simply set it to 75Hz on 1680x1050 through default screen adjustments? Seems to me my monitor "supports" it.

Regards,
Roobir

 

[Roobir]

So far it works on the following:

- Samsung 2232GW with Nvidia 9800gt
- Samsung 2232GW with ATi HD4890
- Samsung T220 with a Nvidia 9800GTX+

I'd appreciate it if you also post your findings with these rates

Cheers,
Roobir

 

[Rudimental]

Can anyone tell me what the consequences are for forcing this and why I cannot simply set it to 75Hz on 1680x1050 through default screen adjustments? Seems to me my monitor "supports" it.

Your default screen adjustments are based on the screen's EDID. Grab Moninfo if you want to see a list of standard refresh rates/resolutions for your monitor. I have no idea about the consequences of running that monitor in 1680x1050 at 75hz. I'm guessing it may be similar to overclocking your CPU, i.e. putting more strain on components, but I have no idea of what sort of tolerances are involved here.

 

[AnomalyNexus]

I wouldn't feed an LCD 75hz. Stick to 60hz.

Zero noticeable benefit but potentially damaging to the LCD.

 

[Roobir]

I wouldn't feed an LCD 75hz. Stick to 60hz.

Zero noticeable benefit but potentially damaging to the LCD.

Any chance of damaging the graphics card? Wouldnt want that tbh

 

[AnomalyNexus]

Any chance of damaging the graphics card? Wouldnt want that tbh

None.

 

[sn3rd]

How sure are you that the LCD is actually displaying 75 frames per second?

The LCD will just drop the extra frames.

 

[The_Techie]

How sure are you that the LCD is actually displaying 75 frames per second?

The LCD will just drop the extra frames.

Well, a 2ms response time would equal a theoretical maximum of 500FPS that will be capable of being displayed, though DVI syncs at 60Hz if I'm not mistaken. It's an interesting question.

 

[sn3rd]

Well, a 2ms response time would equal a theoretical maximum of 500FPS that will be capable of being displayed, though DVI syncs at 60Hz if I'm not mistaken. It's an interesting question.

Not the same thing.

Response time refers to the time for individual pixels to change from light to dark.

Refresh rate refers to the rate at which an LCD can update an image.

Theoretically, a 2ms response panel is able to change each pixel 500 times per second, but that does NOT mean that the LCD is able to draw 500 frames every second.

See thread here

 

[AnomalyNexus]

Some panels do actually try to display 75hz even though they are spec'd for 60hz. (DVI) Sony comes to mind. The output look sort-of messed up but still l readable.

The LCD will just drop the extra frames.

:erm: Even if you drop 15 refreshes the timing between each refresh will still be off by ~3ms.

 

[sn3rd]

Some panels do actually try to display 75hz even though they are spec'd for 60hz. (DVI) Sony comes to mind. The output look sort-of messed up but still l readable.


:erm:Even if you drop 15 refreshes the timing between each refresh will still be off by ~3ms.

Fair point.

 

[The_Techie]

Not the same thing.

Response time refers to the time for individual pixels to change from light to dark.

Refresh rate refers to the rate at which an LCD can update an image.

Theoretically, a 2ms response panel is able to change each pixel 500 times per second, but that does NOT mean that the LCD is able to draw 500 frames every second.

See thread here

Not entirely true, actually. Refresh rate dictates how often a new frame is received from the graphics processor, however response time dictates the amount of time it takes a pixel to change from one colour to another and then back (grey to grey, though it's becoming more common to show figures only from one colour to another and not back), which at 2ms = 500 times a second which equals 500FPS (theoretically) though let's say you'll only get half that. This implies that an LCD is capable of rendering 250FPS but it only receives frames to render at the speed of the refresh rate.

Much of the discussion of refresh rate does not apply to the liquid crystal portion of an LCD monitor.

The closest thing liquid crystal shutters have to a refresh rate is their response time.

However they also have a refresh rate that governs how often a new image is received from the video card (often at 60 Hz).

Source

 

[sn3rd]

Not entirely true, actually. Refresh rate dictates how often a new frame is received from the graphics processor, however response time dictates the amount of time it takes a pixel to change from one colour to another and then back (grey to grey, though it's becoming more common to show figures only from one colour to another and not back), which at 2ms = 500 times a second which equals 500FPS (theoretically) though let's say you'll only get half that. This implies that an LCD is capable of rendering 250FPS but it only receives frames to render at the speed of the refresh rate.



Source

Close to what I said, but no; the PIXELS are capable of switching 250 times per second, but an entire frame can't necessarily be drawn 250 times per second.

Sure you can up the frame rate out of your graphics card, but a monitor with a maximum refresh of 60Hz still won't be able to display 75Hz

 

[The_Techie]

Close to what I said, but no; the PIXELS are capable of switching 250 times per second, but an entire frame can't necessarily be drawn 250 times per second.

Like I said, let's take half of 500. We can even take half of that, or even half of that and still end up with a higher possible rate of rendering frames than the refresh rate, however it will be limited by the amount of frames received even if it is capable of rendering more. Was just to illustrate a point.

Sure you can up the frame rate out of your graphics card, but a monitor with a maximum refresh of 60Hz still won't be able to display 75Hz

Indeed, if the monitor itself can't receive more than 60Hz it will just drop the extra frames, however that is not what my first post was about. My original point, however, was that (according to what I've read) DVI syncs at 60Hz so I'm not entirely certain that changing the refresh rate of the output signal will result in more frames passing over normal DVI. Though it might just adjust to the new output frequency, I don't know, that's why I said it's an interesting question

 

[sn3rd]

Like I said, let's take half of 500. We can even take half of that, or even half of that and still end up with a higher possible rate of rendering frames than the refresh rate, however it will be limited by the amount of frames received even if it is capable of rendering more. Was just to illustrate a point.

Indeed, if the monitor itself can't receive more than 60Hz it will just drop the extra frames, however that is not what my first post was about. My original point, however, was that (according to what I've read) DVI syncs at 60Hz so I'm not entirely certain that changing the refresh rate of the output signal will result in more frames passing over normal DVI. Though it might just adjust to the new output frequency, I don't know, that's why I said it's an interesting question

Yes, and I agree that the individual pixels would be capable of this IN THE BEST CASE. But this is not the case for an entire frame. Switching a single pixel from black to white and back to black can be done MUCH faster than switching it from an intermediate cyan to an intermediate yellow. Thus, yes, if you wanted to watch an alternately flashing black and white screen on your monitor, then sure, the response time is WAY better than what your refresh is giving you.

In reality, we have a few data rates that play a role here. The graphics card outputs frames at a specific rate. This rate needs to be synchronised with the monitor (as mentioned in an earlier post). The extra frames won't simply be dropped; they cause the graphics card and monitor to lose synchronisation. So if the graphics card is outputting 75Hz, and you're actually getting a picture on the monitor, then the monitor HAS to be synchronised at 75Hz. The monitor's internal circuitry has limitations of its own. It may or may not be able to display a 75Hz image properly (or at all), even if the monitor is able to receive the image at 75Hz.

Regarding DVI's clock, the frame rate is limited by the resolution. At lower resolutions, DVI is able to up the frame rate. Most importantly, DVI clock != DVI framerate.

 

[Roobir]

All I can say is that my FPS games are running smooth again. For me going down from 100Hz refresh rate to 60Hz in Counter-Strike was visibly noticeable in my onscreen movement of the mouse. Now on 75Hz it looks allot better again

 

[Roobir]

Hi everyone,

I was going through my old posts and I found this little gem. I am now on a 120Hz screen and I was wondering what everyone thought about high refresh rate screens? I see 144Hz is now the new "in" thing?

Also; Necromancer