DVI has lower max res than VGA?

rjolin01

[H]ard|Gawd
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I have an Acer P241W monitor and when I have my VGA cable connected to VGA in on monitor with DVI adapter on the GPU I get max resolution of 1600x1200. Now when I hook up a DVI cable to DVI in and to video card my resolution drops to 1024x768. Anyone know why this is and how I can fix it? Thanks for any help.
 
Have you actually tried changing the resolution in the control panel? If so (and it simply can't go any higher), you may need a dual link DVI cable to enable higher resolutions on that particular video card. Check your DVI cable...is it missing two rows of pins in the middle?

dvi_connector_types.gif
 
Have you actually tried changing the resolution in the control panel? If so (and it simply can't go any higher), you may need a dual link DVI cable to enable higher resolutions on that particular video card. Check your DVI cable...is it missing two rows of pins in the middle?

dvi_connector_types.gif

I highly doubt that the monitor even listens on the extra dual-link pins, so a dual link cable won't do much good...
 
Single link DVI should support up to 1920 × 1200 @ 60 Hz. Unless the display limits its resolution when using DVI, you should be able to increase the resolution. Installing a driver monitor as suggested may be a solution.
 
It's an well-known EDID problem:

http://www.hardforum.com/showthread.php?t=1382032
http://forums.overclockers.com.au/showthread.php?p=9020937
http://www.rage3d.com/board/showthread.php?t=33935051
http://forums.nvidia.com/index.php?showtopic=62911&st=20&p=411726&#entry411726

Overdriven said:
you may need a dual link DVI cable to enable higher resolutions on that particular video card

I presume you meant monitor instead of video card, because that doesn't even make sense. It's a 1920x1200 monitor, and dual-link DVI is only needed for 2560x1600 (and true 120Hz monitors).
 
i updated drivers although i think i already had most current. still same thing. I have looked at the addapter for the vga and it is the dual link one but my actual dvi is not dual link so Overdriven may be right I will look into purchasing a dual link. Now if max res is 1600x1200 with vga adapter will actual dvi be higher?
 
i updated drivers although i think i already had most current. still same thing. I have looked at the addapter for the vga and it is the dual link one but my actual dvi is not dual link so Overdriven may be right I will look into purchasing a dual link. Now if max res is 1600x1200 with vga adapter will actual dvi be higher?


You do not need dual-link for 1920x1200.
 
refardless of evilsofa attempting to yell at me on my own thread. I am pretty sure that i need a dual link dvi cable . I found a site that talks about dvi and it says single supports up to 1080 and dual link supports all. now 1080 would be as if my monitor runs say 1920x1080. but it doesnt it runs 1920x1200. also my monitor does have a dual-link connector as it has the 24 pins connector. so i will get me a dual link and hope that it will work and will let u know.
 
it wont help. only reason that would work is if your single link cable is broken. i have single link and do 1920x1200. read the threads posted about EDID problems.
 
1920x1200 resolution = 2,304,000 pixels
2,304,000 x 60Hz = 138,240,000 pixels per second
138,240,000 x 24 bits per pixel = 3,317,760,000 bits per second, or 3.317 Gb/sec

1920x1200 @ 60Hz x 24 bits per pixel = 3.317 Gb/sec
2560x1600 @ 60Hz x 24 bits per pixel = 5.90 Gb/sec
Single-link DVI maximum speed: 3.96 Gbit/s

As you can see, 1920x1200 at 60Hz is well within single-link DVI capacity, while 2560x1600 at 60Hz requires dual-link. If you're wondering "but LCD monitors are 6-bit or 8-bit, not 24-bit!", well, I don't understand enough to explain but that's how RGB works.

See also:
List of digital video interconnect bandwidths
DVI clock and data relationship
24-bit RGB representation
 
1920x1200 resolution = 2,304,000 pixels
2,304,000 x 60Hz = 138,240,000 pixels per second
138,240,000 x 24 bits per pixel = 3,317,760,000 bits per second, or 3.317 Gb/sec

1920x1200 @ 60Hz x 24 bits per pixel = 3.317 Gb/sec
2560x1600 @ 60Hz x 24 bits per pixel = 5.90 Gb/sec
Single-link DVI maximum speed: 3.96 Gbit/s

As you can see, 1920x1200 at 60Hz is well within single-link DVI capacity, while 2560x1600 at 60Hz requires dual-link. If you're wondering "but LCD monitors are 6-bit or 8-bit, not 24-bit!", well, I don't understand enough to explain but that's how RGB works.

See also:
List of digital video interconnect bandwidths
DVI clock and data relationship
24-bit RGB representation

LCD panels are 6/8/10 bit's PER sub-pixel. You'd have 6/8/10-bits for red, 6/8/10-bits for blue, and 6/8/10-bits for green. So the total signal would have to have 18/24/30 bits.

Of course, DVI only provides 24-bit color, so 6-bit LCDs ignore parts of each color element and 10-bit panels would have to make up extra information.
 
LCD panels are 6/8/10 bit's PER sub-pixel. You'd have 6/8/10-bits for red, 6/8/10-bits for blue, and 6/8/10-bits for green. So the total signal would have to have 18/24/30 bits.

Of course, DVI only provides 24-bit color, so 6-bit LCDs ignore parts of each color element and 10-bit panels would have to make up extra information.

Ah, now I got it. Each pixel is made of 3 sub-pixels, so each 8-bit pixel requires 24 bits of bandwidth. Thanks!
 
ok i have alot of info here yet i am not sure if i missing it but is there an answer somewhere in this all for my problem?
 
I think I can tangent off the DVI cable pin layouts...
VGA is an analog signal I believe, so if you use a DVI-A cable to go from your graphics card to your monitor, you may get your full resolution back. Try it and see what happens.
 
Presumably if your resolutions are limited when using DVI then the EDID information and/or the drivers are crap. In either case, you should be able to override this using the ATI's or nVidia's respective control panels.
 
refardless of evilsofa attempting to yell at me on my own thread. I am pretty sure that i need a dual link dvi cable .

Yelling or not, evilsofa is right. A dual link cable will do nothing. The extra links won't even be connected to anything on the monitor side as this is a single link only monitor.

As stated it is an EDID problem with the monitor so the resolution read by the graphics card is incorrect.
 
guess no one has a real solution just an idea what it is. i appreciate everyones help just want to know how to fix this problem.
 
I am sorry to see no one post a solution, I was interested in the topic as well.
 
how do i fix this problem

Provide more info please.

1) What O/S are you running?

2) Is the system in your SIG current? What driver version are you running? 190.38 are the newest, are these the ones you tried?

3) Have you tried any of the EDID reg/file mods that EvilSofa has linked to in the other threads? Also the fix that another user said in that thread about starting the computer with the screen off, and turning it on once your O/S has booted.

4) Have you gone into the nVidia control panel and checked what resolutions are supported?

5) Are you going from DVI port 1 on the first video card to the DVI port on the monitor? DVI port 1 on an nVidia card is the one closest to the motherboard/farthest from the slot retention screw/clip.

6) You are not connecting VGA and DVI on the video card at the same time are you? Ie. you are not using both ports of the video card on one monitor are you?

- The monitor doesn't support Dual-link DVI physically so don't waste your money.

- Try and start from scratch. Uninstall the nVidia drivers from the Add/Remove Control Panel, find Driver Sweeper from Guru3d and follow the instructions to completely wipe your drivers. If you have any custom profiles save them elsewhere.

Driver Sweeper is here:

http://downloads.guru3d.com/Guru3D---Driver-Sweeper-%28Setup%29-download-1655.html

Use it. It's your friend. It will remove pretty much every last vestige of the ForceWare drivers.

Try "flipping" the adapters in their slots. The one 8800GT might be better at reading the screen than the other.


No offence, but if you want a solution, you have to answer questions for people to help you out. Just asking for a "Fix from God" doesn't magically bestow one on you ;)
 
Well seeing as I never had this problem I was unaware there were question that needed to be answered since no one asked majority ones you asked. If I knew all this would I be here trying to figure it out? Probaly not. But thanks and I will give your methods a shot.
 
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