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Low Refresh Rate When Using HDMI on LCD TV

Last response: in Graphics & Displays
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June 22, 2009 4:28:01 AM

I while back I received an1080i LCD TV which I began using as my monitor. Since it lacks any DVI inputs, I just used a DVI to VGA adapter and went with a 1440x900 resolution with 60hz refresh rate. Just recently it occurred to me to purchase a cable to convert the DVI output into an HDMI input that my TV supports. When I got the cable and began using it, I found that I could not get my display to appear at my 60hz 1440x900 resolution . after some setting adjustments I got it to boot and was able to set my resolution up to 1920x1080, but it would only let me use a refresh rate of 30hz interlaced, which makes windows appear jittery and is very hard to use for more than a few hours without my eyes straining. I checked out the Nvidia control panel and it detected my HDTV correctly, and gave me a 1080i50 signal option, but when the refresh rate on my TV goes above 30 hz at this resolution any text become jagged and unreadable, and any icons on my desktop have very jagged edges. The screen also flashes briefly and randomly. I have done extenxive google searching to no avail.

The monitor in question is a 19 inch Element FLX-1910 TV
I have an Nvidia GeForce GTX 260 as my display adapter (drivers updated)
I am also using Windows Vista SP1 (Updated as well)

Despite not being a huge issue, it is still an annoyance that I would rather not deal with and I would greatly appreciate any advice anyone has to give. I just don't want to give up this beautiful display for a minor annoyance!

June 22, 2009 5:38:56 AM

Xiahoudun32 said:
I while back I received an1080i LCD TV which I began using as my monitor. Since it lacks any DVI inputs, I just used a DVI to VGA adapter and went with a 1440x900 resolution with 60hz refresh rate. Just recently it occurred to me to purchase a cable to convert the DVI output into an HDMI input that my TV supports. When I got the cable and began using it, I found that I could not get my display to appear at my 60hz 1440x900 resolution . after some setting adjustments I got it to boot and was able to set my resolution up to 1920x1080, but it would only let me use a refresh rate of 30hz interlaced, which makes windows appear jittery and is very hard to use for more than a few hours without my eyes straining. I checked out the Nvidia control panel and it detected my HDTV correctly, and gave me a 1080i50 signal option, but when the refresh rate on my TV goes above 30 hz at this resolution any text become jagged and unreadable, and any icons on my desktop have very jagged edges. The screen also flashes briefly and randomly. I have done extenxive google searching to no avail.

The monitor in question is a 19 inch Element FLX-1910 TV
I have an Nvidia GeForce GTX 260 as my display adapter (drivers updated)
I am also using Windows Vista SP1 (Updated as well)

Despite not being a huge issue, it is still an annoyance that I would rather not deal with and I would greatly appreciate any advice anyone has to give. I just don't want to give up this beautiful display for a minor annoyance!



Hate to say it, but everything is performing normal. 1080i means that on any given frame, only every other row of pixels is updated. In other words, for the first frame, only rows 1, 3, 5, 7, and so on are refreshed. On the next frame, rows 2, 4, 6, 8, and so on are refreshed. The result is that any given row of pixels is only being updated 30 times a second. This kind of refreshing is called interlacing (hence the i at the end of 1080i) and it's all your TV can support when working at 1920x1080.

The spec sheet for your TV says it supports 720p (1440x900 @ 60 hz non-interlaced), which, according to your post, was working fine before you started using the DVI -> HDMI cable. Was there something about using the VGA cable that you didn't like that caused you to switch? It might be that your TV automatically defaults to 1080i when the HDMI connection is in use.


Edit: Seems there's such a thing as HDMI and HDMI-PC. Wonder if that could be a cause...
June 22, 2009 5:21:11 PM

Its' not that I dislike using VGA, I just like the higher resolution because I can run most of my games swimmingly at that resolution. I just wanted to know whether or not I could get it to stop the slight shaking on windows when doing regular browsing. It also appears that I am using standard HDMI, not HDMI-PC.

Thanks for the reply.

EDIT: One thing I also just noticed was that, when I put it up to 50hz refresh rate, my screen goes black for a second, then shows the display at a proper 50hz only before becoming pixelated.

!