Acceptable VGA cable distance

[Red Squirrel]

I'm thinking of using a secondary machine with synergy to have a 3 monitor setup for a few reasons that make this better. Rather than having two machines at my desk, which I don't really have room for, I was thinking of putting one, or perhaps even both, in my server room. The advantage to this would also be lack of noise and centralizing power backup.

This would require 3 (and more in the future if I add more screens) VGA cables going to the server room. Thankfully it's just under my office, so we're probably looking at like 50 feet at very most (taking cable management into account). At our church we have a cable that is 100+ feet for the projector and it works fine, but at home, for gaming or other high definition stuff, would I notice any issues by having such a long cable?

Is there a better way to send multiple video signals? Some kind of multiplexer that uses fiber? (I have tons of fiber here provided the connectors would be right)

What about DVI? I think I could do DVI as well, I'd have to double check.

 

[Aikouka]

From what I've read, acceptable VGA runs depend on resolution. It's an analog connection using 15 pins (hence why the connector is called a DB15), so I'm not sure if you could just run some fiber connection without converters.

 

[Ferzerp]

It depends on cable quality (this is one cast where buying quality cables is important) and resolution mostly. Projector picture quality really isn't that good, so you probably don't notice it.

DVI is a far better option. If the signal gets there error free, it will look correct. With VGA, there will always be some issues, especially with a 50 foot cable.

 

[Red Squirrel]

Good to know, I've been looking online and it seems I may be fine with a quality cable. I will have to measure around to see exactly what I need. I've been thinking it further and I will probably be able to get away with 25 feet. Definitely going to look at DVI as well. Pretty sure I can do that, I just have to double check the back of the monitors but the video cards are all DVI and I've been using adapters, so if the monitors have DVI and I'm buying new cable anyway make sense to just go DVI.

What about USB's tolerance, is it pretty much same idea? Use a high quality cable? I'd be using it for keyboard, mouse, and have another spare for stuff like USB stick, etc. Not sure yet if the main PC will also reside there though, but in a way it would be nice to have a completely quiet office.

 

[KingFatty]

VGA can start looking noticeably messed up with long cables. Years ago I worked at a store called Computer City and they had a "monitor wall" setup with monitors across the wall. The source signal was from one side, so the nearby monitors had short cables and the monitors on the other end had long cables. You'd see the different effect on VGA cable length, where the long cables caused some odd effects like fuzzy distortion etc. VGA is an analog signal, so as the length increases that alters the different signals and leads to distortion.

Definitely go DVI, it's digital so there isn't distortion, it will look crystal clear until you exceed the limits, so you don't get the gradual decline like VGA as length increases.

Here is some info on DVI cable length:
Cable length
The maximum length of DVI cables is not included in the specification since it is dependent on the pixel clock frequency, and hence the video mode's bandwidth requirements (which is a function of resolution and refresh rate). In general, cable lengths up to 4.5 m (15 ft) will work for displays at resolutions of 1,920 × 1,200. This resolution will work even up to 10 m (33 ft) if the appropriate cable is used. Cable lengths up to 15 m (50 ft) can be used with displays at resolutions up to 1,280 × 1,024. For longer distances, the use of a DVI booster is recommended to mitigate signal degradation. DVI boosters may use an external power supply.

 

[Red Squirrel]

Seems like DVI is the way to go then. Does this look good? Think I'll buy 3 of these and 2 long USB cables for keyboard/mouse as well as 2 rackmount cases and move the stuff over. Just need to measure and confirm the length and leave room for some slack.

http://www.tigerdirect.ca/applicatio...700&CatId=4465

Though I'm still debating if I want to keep the main machine upstairs but it would be kinda neat to have it all downstairs.

 

[fuzzymath10]

Just as important for VGA if you go that route is the quality of the signal coming out of your graphics card. In fact, I have never been cable bottlenecked to the point of being significantly visible; it's always been the quality of the signal from the DAC.

 

[jaqie]

check monoprice.com for cables. better quality and better prices.