Question about monitor cable length

[Mats]

I've known for a long time that the cable length for the monitor is better kept as short as possible. I have never tried with longer cables though, so I don't know if there's some kind of limit or so.

Are there any differences between DVI (digital) and VGA/CRT (analog) cables in this issue?

I know this have been discussed before, but I haven't seen anything about DVI.

If I could put the computer in another room it would probably mean that I gave up the eternal quest for a silent PC, and that's something you wouldn't like...
On the other hand, I prefer this solution (IF IT'S POSSIBLE!!!!) with extension cables (and a DVD case if I'm really lazy) rather than the popular use-a-2.5"-and-put-the-big-HD-in-the-closet advice. The latter idea costs more and reduces only one source of noise (and maybe 15 W from the PSU + HD fan + some heat). I still have at least PSU, CPU and GPU to deal with.

I think I can make my computer really low noise since I got a big case with lots of space. The thing is that I really don't think that PC (or Apple) cases looks good at all (not even Thermaltake! ), I'd rather not see it. Yeah, some of them looks cool, Hoojum and Hush for instance, but I don't want it in the only single room I live in. The hi tech geek factor gets too big!

[Edward Ng]

Are there any differences between DVI (digital) and VGA/CRT (analog) cables in this issue?

Yes and no; allow me to explain...

There are actually two parts to the standard DVI-I interface, analogue and a digital part. For digital flat panel displays that have DVI-I hookups, the DVI-D (digital) portion of the DVI-I interface is almost always the part being used. In that case, the length of the cable isn't that important; as long as there isn't catastrophic signal degradation such that the 1s and 0s don't make it (I'm assuming DVI-D doesn't suffer from, "jitter,"-type effects like audio does), you will not suffer noticeable image quality affects. If you're using one of the rare flat panel displays that only utilize the DVI-A (analogue) portion of the DVI-I interface, or maybe one of the not quite as rare, but still rare, DVI-enabled CRT displays, which also relies on the DVI-A portion of the DVI interface, cable length still comes into play.

I wish I could tell you how analogue/VGA cabling compares to DVI-A in terms of cable length image effects, but I don't really know.

I hope that helps.

-Ed

[Mats]

Thanks a lot Edward!
Yeah, I've heard about the different kinds of DVI. I just assumed that ANY analog monitor signal is not a good idea together with long cables, so I was really hoping that the digital ones are better.
Less than 5 meters would be enough, do you think that would work? Does anybody know some good reading about this?

How important is cable quality? I guess it's less important than with the analog ones.

[8300ati]

http://www.scala.com/hardware/dvi-vga-cable.html

[Mats]

Thanks 8300ati!!
Now I just need a room to put in.... have we heard that before?

[Metaluna]

DVI digital cables do have their limits. Just to add a data point from personal experience:

I have a Belkin 2-input DVI KVM switch that I use with my Samsung flat panel at 1600x1200@60Hz to switch between two DVI-equipped PC's. Each computer is connected to the switch with a 6-foot DVI-D cable, and another 6' cable to the panel. The display is nearly flawless but I have noticed some defects that are not there when a single monitor is connected. For example, in Outlook, in the main Inbox pane, there is a little dotted box that appears around the selected message to highlight it. The dotted lines are rock solid when only a single computer is connected to the panel, but they shimmer and flash when the KVM and extra cabling are inserted. I assume the dot pattern is pushing the cable bandwidth to the limit Other than that the display looks great, though I wouldn't recommend the Belkin switch in general due to its unreliable handling of the USB interfaces.

[the_e_dean]

I have run a 50ft VGA cable for a second monitor at a dentist office with no trouble, picture is as clear as the primary monitor with a standard length (6ft?) cable.

Dean

[ghowarth]

I have a 5 metre VGA cable, which gives perfect reproduction at 1280x1024 on TFT. Just make sure the cable is shielded - more expensive, but at first I bought an unshielded one, and the signal was unacceptable.

[wim]

Less than 5 meters would be enough, do you think that would work?

as long as you get the heavy cable it will be fine.

i want to point out that even 10 meters of analog VGA cable pushing through 1600x1200 at 75Hz doesn't just plain "not work" ... you may begin to notice some smearing and smudging in the signal (the only thing i could tell at this distance was intensity getting 'wiped' horizontally a little bit, and it took me until i knew what to be looking for to really notice it). whether this degradation in signal irritates you more than having an audible computer is another issue entirely.