Monitor refresh rate problem.

Zalkard

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Hello,

I was trying to change the refresh rate of my monitor from 60hz to 75hz.
It is rated to run at 75hz, although in the resolutions tab (Advanced) on windows, it only shows 50, 59, and 60hz to be selected. Aswell as naming the monitor "Generic PnP Monitor". I've tried using the program called CRU, yet can't seem to get it to run at 75hz, or even being able to select 75hz.

Answer are very welcome.

-Zalkard.
 
Solution
I think it's a question of bandwidth on the signal cable. 1920x1200p60 (the maximum for HDMI 1.0) indicates a transfer rate of 414,720,000 bytes per second (figuring 3 bytes per pixel, and no compression). 1920x1080p75 requires a transfer rate of 466,560,000 bytes per second. 1280x720p75 only requires 207,360,000 bytes per second. That's why 120hz 3d monitors usually require dual-link dvi or displayport to take a 1920x1080p120 signal.

The downloadable pdf specification does indicate the monitor can take a 56-75 Hz vertical refresh, but that doesn't necessarily mean it can handle 75 Hz at full native resolution. The monitor doesn't have a displayport jack, and I don't find any indication that it supports HDMI 1.3 or dual-link DVI.

Zalkard

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Monitor: LG Flatron E2260
Resolution: 1920x1080
Cable: HDMI to DVI cable (One side HDMI, one side DVI).
 

Zalkard

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I have tried that, multiple times. But it doesn't seem to work. In the resolutions menu - Advanced it doesn't say anything above 60hz that I can select. The monitor is also suddenly called "Generic PnP Monitor" Any ideas on what to do? I've set it to 75hz on CRU.
 
There's also the problem that HDMI 1.0 only supports up to 1920x1200p60. HDMI 1.3 and later support higher resolutions and refresh rates, but that requires that both the video card and the monitor be HDMI 1.3 compliant (and possibly the cable as well). If one of them doesn't specify which version of the HDMI spec it complies with, safer to assume it's HDMI 1.0. A DisplayPort or Dual-Link DVI cable and connection would have a better chance of working at 75 Hz.

While we're at it, where are you seeing that monitor rated for 75 Hz? I see no such indication in the specs on the LG website, except for supporting 75Hz on the AC power connection (from the wall, not the data signal from the computer).
 

Zalkard

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Strangely, I can't find it either right now. Might it have been a typo somewhere on the website?
And for examply on Battlefield 3, at 1280x720 I have the option to use 75hz, and can definitely feel the difference from 60hz.
 
I think it's a question of bandwidth on the signal cable. 1920x1200p60 (the maximum for HDMI 1.0) indicates a transfer rate of 414,720,000 bytes per second (figuring 3 bytes per pixel, and no compression). 1920x1080p75 requires a transfer rate of 466,560,000 bytes per second. 1280x720p75 only requires 207,360,000 bytes per second. That's why 120hz 3d monitors usually require dual-link dvi or displayport to take a 1920x1080p120 signal.

The downloadable pdf specification does indicate the monitor can take a 56-75 Hz vertical refresh, but that doesn't necessarily mean it can handle 75 Hz at full native resolution. The monitor doesn't have a displayport jack, and I don't find any indication that it supports HDMI 1.3 or dual-link DVI.
 
Solution

Zalkard

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Alright, thanks alot for the help :)
 

Zalkard

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It does support dual link dvi I have figured out, so does the graphics card.
 
I hope you're not assuming that because a dual-link dvi cable can go in. The female dvi connectors often have the extra holes for dual-link dvi to reduce the chance of unintentionally damaging the pins, but that doesn't automatically mean the monitor (or video card) actually has them connected to anything else.
 

Zalkard

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I had found the specs of the monitor and it told me it was capable of running at 75. I read that a single link dvi cable was limited to 60hz max. I have no idea why but yesterday, in the dropdown menu in advanced resolutions, I was able to select 75hz, and also able to play on 1920x1080 @75hz on BF3 video settings. So I am quite confused right now.