LG HDTV as a PC monitor problem

Steve M

Steve M

Steve M

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I've just bought a 42" LG LCD TV and i'm having a problem with using it as my PC monitor over VGA.

It's native resolution is 1920 x 1080 but when i select that resolution in Windows 7 there is a black bar on the left hand side of the screen and on the right hand side part of the desktop is missing. I've got an nvidia 8800GT graphics card and the only way i can get the desktop to display on the whole of the screen is to create a custom resolution in the nvidia control panel of 2020 x 1080 which works fine but the text is slightly blurred and doesn't look as crisp as in the native res.

Any ideas?

When using HDMI the entire screen is displayed perfectly, but the quality is poor compared with over VGA.
 
Yes it does have a 'just scan' option, but this is greyed out when using VGA. Over VGA the only selectable options in that menu are 16:9 and 4:3..
 
Just to add, my XBOX 360 works fine over VGA on 1920 x 1080 so not sure why my PC is having a problem when trying to run the same resolution?
 
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CaptainCrash said:
When you say the picture is "poor" using HDMI compared with VGA, poor in what sense?
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In the sense is just looks much better over VGA, crisper, clearer and colours more vibrant compared with HDMI. Text also much sharper as looks fuzzy with the HDMI.

I'm guessing this is just the situation when using a HDTV as a PC monitor? My previous display was a 28" Hanspree monitor (purchased from OCUK) and with that HDMI and VGA were identical for displaying my PC and you would struggle to tell which was which, but before using that i had a 32" HDTV (I forget the brand) and it was the same situation i have now: VGA just looked much better.
 
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Steve M said:
In the sense is just looks much better over VGA, crisper, clearer and colours more vibrant compared with HDMI. Text also much sharper as looks fuzzy with the HDMI.
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If anything, the picture should be better over HDMI - I'm looking right now at an LG 42LK450 connected as a secondary monitor (using a DVI-HDMI cable), and the text is about as sharp as you could reasonably expect from 1080p on a big screen.

HDTVs can be tricky when used as PC monitors though, they all have their individual quirks and gotchas, and they rarely work well out of the box. What model is your LG, what graphics card, is it a straight HDMI-HDMI cable or a DVI-HDMI converter?
 
Steve M said:
Yes it does have a 'just scan' option, but this is greyed out when using VGA. Over VGA the only selectable options in that menu are 16:9 and 4:3..
Click to expand...

As you'd expect. "Just scan" tells the display that all the data it is receiving is image data. So it displays all of it. This is the default for VGA connections, which are mostly used with PCs. Therefore this opition would be greyed out, since it is assumed to be on always when connecting via VGA.

As opposed to a TV/VCR connection (via HDMI), where some of the data sent is not designed to be displayed (I'd have to Google to tell you exactly what). If all the data *was* displayed, there would be a border around the picture which would probably look like white noise. Therefore the display has to ignore a certain margin of the signal and enlarge the middle of the screen to take up the whole screen. This I believe is called "overscan".

If you are using a source, such as a PC (or XBox?) that only sends picture data and nothing else, and connects via HDMI, then you need to tell the TV this. Connect your source via HDMI, then turn on the "just scan" option.
 
CaptainCrash said:
If anything, the picture should be better over HDMI - I'm looking right now at an LG 42LK450 connected as a secondary monitor (using a DVI-HDMI cable), and the text is about as sharp as you could reasonably expect from 1080p on a big screen.

HDTVs can be tricky when used as PC monitors though, they all have their individual quirks and gotchas, and they rarely work well out of the box. What model is your LG, what graphics card, is it a straight HDMI-HDMI cable or a DVI-HDMI converter?
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My TV is an LG 42LK450!

My GFX card is an Nvidia 8800GT and was using a DVI to HDMI cable.

IN my opinion it just looks a bit crap over HDMI. Exactly the same issue with my XBOX, looks miles better over VGA.
 
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FoxEye said:
As you'd expect. "Just scan" tells the display that all the data it is receiving is image data. So it displays all of it. This is the default for VGA connections, which are mostly used with PCs. Therefore this opition would be greyed out, since it is assumed to be on always when connecting via VGA.

As opposed to a TV/VCR connection (via HDMI), where some of the data sent is not designed to be displayed (I'd have to Google to tell you exactly what). If all the data *was* displayed, there would be a border around the picture which would probably look like white noise. Therefore the display has to ignore a certain margin of the signal and enlarge the middle of the screen to take up the whole screen. This I believe is called "overscan".

If you are using a source, such as a PC (or XBox?) that only sends picture data and nothing else, and connects via HDMI, then you need to tell the TV this. Connect your source via HDMI, then turn on the "just scan" option.
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Errrm, it was me being a bit dumb (new tv and all that, not sure of the menus) i found an 'auto size' option in a sub menu which fixed the issue i raised in my initial post.

Cheers for your help :)
 
Out of curiosity, how far do you find you have to sit from a your 42" screen? I'm about to try a 32" as a PC monitor, it's a bit frightening how big they are up close :p
 
Steve M said:
My TV is an LG 42LK450!

My GFX card is an Nvidia 8800GT and was using a DVI to HDMI cable.

IN my opinion it just looks a bit crap over HDMI. Exactly the same issue with my XBOX, looks miles better over VGA.
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Maybe the default presets on the VGA input are closer to your own preferences than the ones on HDMI - you really need to select Expert1 or Expert2 in "Picture Mode" and fiddle with it until it's more to your liking.

One potential gotcha is that you *shouldn't* label the HDMI input you're using as "PC" (under Input > Input Label in the main menu) - I don't know if you've done this, but it applies a non-defeatable edge enhancement, which causes nasty ringing and haloing around text. Pretty stupid idea, as you'd think a "PC" setting would disable any processing, but there you go... your best bet is to leave it blank, and fiddle with the horizontal and vertical sharpness settings in one of the "Expert" picture mode settings. I've found that 34:56 (horizontal:vertical sharpness) works for me, but it depends on what panel you've got... there's a lottery going on, and you could have an LG S-IPS, an AUO A-MVA or a Chi Mei Innolux S-MVA panel, depending on when and where you bought it.

These TVs have masses of advanced picture adjustments, which is a bit of a mixed blessing... you should eventually be able to get a very nice picture, but there's a considerable learning curve, and it will take time and patience.

If you check out the dedicated LK450 thread at AVSForum you'll find loads of useful info, and also in the one for its predecessor the (very similar) LD450, although I should warn you they're rather long. :D
 
FoxEye said:
Out of curiosity, how far do you find you have to sit from a your 42" screen? I'm about to try a 32" as a PC monitor, it's a bit frightening how big they are up close :p
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I use it mostly for multimedia stuff, I definitely wouldn't want to use it as a "regular" monitor. If I sit close enough to see Windows elements at the default DPI without eyestrain, it's way too overpowering... I do the occasional bit of web browsing from around 6-8ft, but I generally have to zoom in using Firefox. My eyesight isn't brilliant though, maybe someone with 20:20 vision would cope better.

A 32" version should be much easier to handle... it's not really *that* big a jump over a 27" 1080p monitor. If you're weighing up your TV options, the LK450 comes highly recommended for monitor use, not least because it will display a 4:4:4 chroma signal without downsampling, and also because of the aforementioned wide range of adjustments available. Look out for that panel lottery though...
 
FoxEye said:
Do you know of any 4:4:4 TVs with an VA panel?
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I'm not sure what current TVs (VA or otherwise) will do 4:4:4 chroma, it's never advertised in the specs and all you can really do is have a look through various AV forums in the hope you'll find someone with relevant info on the model you're considering (mostly a bit of a long shot). I do know the previous Samsung C530/C580 range would do it with HDMI1 input labelled as "PC", so I'd guess its successor the D580 would also... the trouble with that one though is that PC mode locks out most of the advanced picture adjustments, so you'd have to do any calibration using the video card drivers alone. It's possible I guess, but not exactly easy or convenient.

The only one I know of that will *definitely* do 4:4:4 is the LG **LK450 range - having said that, I've seen it suggested (can't remember where) that only the IPS versions will do it, but I can't see any reason why this would be the case, as it's presumably a function of the processing electronics rather than the panel itself.

I actually received the "J" version (S-MVA) of the 42LK450 at first from the big river place, and I've also seen the "D" version (A-MVA) in the place that sounds like a heavenly body with a tail and a long elliptical orbit, so they're around if you take the trouble to find them... I sent the original one back as I specifically wanted the "Y" (S-IPS) version, which I eventually got from the online place which sounds like a dodgy US president after seeing it in their high street equivalent (the Indian food place). From the manufacture dates, it seems that the IPS versions are older stock which is being replaced by *VA alternatives, so you stand a good chance of getting a VA panel if that's what you actually want.

I should say incidentally that the IPS version's allegedly poor blacks are not a problem in practice, at least for me - not as inky as a good VA panel maybe, but certainly good enough seen in isolation, and more importantly, there's plenty of low-level detail, with none of the black crush I've encountered on some VA panels with supposedly "better" blacks. The notorious IPS "white glow" which you mentioned in your other thread isn't a problem in practice either, although if I were sitting right on top of the screen I guess it might be more noticeable.
 
CaptainCrash said:
The only one I know of that will *definitely* do 4:4:4 is the LG **LK450 range - having said that, I've seen it suggested (can't remember where) that only the IPS versions will do it, but I can't see any reason why this would be the case, as it's presumably a function of the processing electronics rather than the panel itself.
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Apparently it's not just the panel that can vary in this model... the entire PCB and electronics inside can also be different. (source: avforums).

Which increasingly makes me feel there's little point in doing too much research beforehand. I might as well buy a TV, take it home and test it, and return it if I get the "wrong" panel / chipset / performance.
 
FoxEye said:
Apparently it's not just the panel that can vary in this model... the entire PCB and electronics inside can also be different. (source: avforums).
Click to expand...
I didn't know that, but it wouldn't surprise me... in that case, perhaps the guy who started the thread has a variant which downsamples chroma over HDMI, hence the complaint about relatively blurry text (AFAIK the VGA input will always faithfully reproduce a 4:4:4 signal).

I think you're right about having to suck it and see, but it just becomes a pain in the derriere when you have to keep returning stuff... very annoying when you get lumbered with what is effectively a different product from the one you wanted, without any way to tell beforehand.
 
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