1080P Monitor won't OC past 66Hz on Single-Link DVI

kewiha · May 20, 2013

Hello,

I am overclocking my BenQ GW2250 1080P monitor which I have connected via single-link DVI. Nvidia's control panel allows me to pick my refresh rate, but the monitor displays a "Out of Range!" pop-up at 67Hz or higher. Knowing 1920x1200P is the highest common resolution single-link supports @60Hz, I did the math and the bandwidth of 1080P@66Hz and 1200P@60Hz are almost the same. From that, I conclude that I am saturating Single-Link DVI.

I checked an my monitor has gold pins in all the sockets (not just the Single-Link ones), which leads me to believe it may overclock higher if I switch to a Dual-Link cable and port, AND the monitor supports it. Dual-Link cables run about $20CAD here, and I would need an adapter to run my VGA monitor off another port. Effectively the cost of upgrading could be as high as $50. I'll be sure to test if the monitor can even display a refresh rate much higher at a lower resolution, but let's assume it can for now.

So, would it be worth getting my hands on a dual-link cable, or would my refresh rate still max out at 66Hz? Thanks for your time, and sorry I couldn't make this post more interesting.

EDIT: After playing with the control panel, my monitor displays the same message when set to 720P@67+Hz. This sounds like the monitor firmware freaking out. There is no discernable ghosting at 66Hz, in spite of it being a V.A. panel. Time to mess with firmware?

SinTonNiSon · May 20, 2013

imagine you can and u get +14 Hz the risk of braking the monitor is worth the Hz?

GoodBytes · May 20, 2013

Dual link cable might work, but does the monitor actually take dual link, or just a dual link port, but really uses the single link pins. BenQ makes 120Hz monitors, so it's logical to use the dual link plugs that they have... larger order.. cheaper it is for them.

That's one thing. The second thing is that, most likely the monitor simply can't pass 66Hz. The reason for this, is that the monitor has a protection system to avoid you burning the panel by doing what you are doing. It must be noted that overclocking a monitor, will allow you to support more frames, but if the panel LCD liquid can't turn fast enough, then all you get a strange blur effect going on on movement, which makes people think they see more frames, but in reality it's just a kinda-of motion blur effect. You can really see that something is strange if you take an overclock panel compared to a true 120Hz monitor.

kewiha · May 20, 2013

imagine you can and u get +14 Hz the risk of braking the monitor is worth the Hz?

According to Nvidia and friends it is a relatively safe procedure. I would only run the overclock while gaming, which would reduce any possible stress dramtically. The monitor is also within the manufacturer's warranty, but I doubt a slightly higher refresh rate would hurt anything. It doesn't seem like I'll be getting any more than the 6Hz overclock unless I flash the firmware, which I am quite reluctant to try.

Dual link cable might work, but does the monitor actually take dual link, or just a dual link port, but really uses the single link pins. BenQ makes 120Hz monitors, so it's logical to use the dual link plugs that they have... larger order.. cheaper it is for them.

That's one thing. The second thing is that, most likely the monitor simply can't pass 66Hz. The reason for this, is that the monitor has a protection system to avoid you burning the panel by doing what you are doing. It must be noted that overclocking a monitor, will allow you to support more frames, but if the panel LCD liquid can't turn fast enough, then all you get a strange blur effect going on on movement, which makes people think they see more frames, but in reality it's just a kinda-of motion blur effect. You can really see that something is strange if you take an overclock panel compared to a true 120Hz monitor.

That seems reasonable, seeing as the monitor won't show over 66Hz at 720P either. There's no motion blur though, as far as I can see with the PRAD test. I suppose being 10% above par is good enough B) .

Thanks for your replies!

GoodBytes · May 20, 2013

Well the PRAD test requires you to take a picture, and set your camera to fix settings so that it doesn't adjust the exposure and things looks better than what they really are.

kewiha · May 20, 2013

I suppose that's a more precise way to do it, but I just dragged the image found here: http://www.prad.de/en/monitore/testsoftware/ghosting-test.html

I found it had no more blur (as far as I can tell) at 66Hz than 60Hz, but it was slightly smoother at 66Hz. I suspect part of that is placebo, but meh. On a side note, I can't seem to recall the code to integrate a link into a string, which would make clicking <this> lead to a URL.