Closed Solved

Dual Monitors with one VGA\DVI Input

Hi Community :hello:

This post is an exact copy of an email I sent my Manager earlier today. However, we're both busy men and I don't think he will get back to me at least for a day or two.

As it stands in [my job] they use a 60 PIN LFH MATROX cable that splits into two VGA in order to achieve dual screens in Windows XP:

http://www.amazon.com/Matrox-VGA-cable-pin-HD-15/dp/B000QBQ2OG

This is how some users are able to run two screens independent of each other.

I remember about a year ago I tried to use a VGA splitter to yield the same result:

http://www.google.com/products/catalog?q=vga+splitter&oe=utf-8&rls=org.mozilla:en-US:official&client=firefox-a&um=1&ie=UTF-8&cid=1535653620349195937&ei=GRcRTdalHYKClAflp9juCw&sa=X&oi=product_catalog_result&ct=result&resnum=5&ved=0CD4Q8wIwBA#

However, I was running Windows Vista (or earlier Windows 7 I can’t remember, but I’m using Windows 7 from now on) and when using this VGA splitter from my laptop to two VGA monitors, the best I could do was get both monitors to display the same thing.

With a little bit of research I figured out that the VGA splitter was only getting one video signal and doing nothing but dishing it out two times to two separate devices.

The preliminary question is: Aren’t these MATROX cables doing the exact same thing? If so no one would be able to have an extended desktop

I did a tiny bit of research before writing this [post] and a user was getting the duplicated screen issue with a certain program but NOT with Windows XP. He was using a VGA splitter like the one I linked to above. And was fully able to use two monitors with one VGA. (I apologize if I'm not supposed to link to other websites!)

http://crunchbanglinux.org/forums/topic/9646/question-dual-monitors-using-vga-ysplitter/


So the big questions I’m having are:
1. Are desktops with only one VGA output able to run dual screens independently?
2. If so, are they only able to do this in Windows XP?
3. If not, can you do this with a DVI to 2x DVI outside of Windows XP?
4. And finally when all said and done, can I run 4 monitors if I had only two DVI ports attached to my PC’s video card (AMD HD 6870)?

I hope this makes sense, I would be happy to clarify if need be.
Thanks Tomshardware Community!
6 answers Last reply Best Answer
More about dual monitors input
  1. 1) Not that I am aware of but if it has two different connecter than yes
    2) Any OS supports multi monitors
    3) Can you even do DVI splitting?
    4) No, this I know for sure, you will need an eyefinity 6 card, you can use two DVI and than 2 display port, or 4 display port, or 1 dvi, 1 vga, and 2 display port, either way you can only have a maximum of 2 VGA,DVI,HDMI connections, so the remaining will need to be via display port, and you would need an active not a passive adapter.
  2. Wow ok that makes a lot of sense, especially Point #4, thank you very much.

    I get what you are saying in Point #1 that if a PC has a VGA and a DVI port on the same card then it should work.

    If I could ask one more question then, whyis this MATROX 60 PIN LFH to 2 x VGA able to support dual monitors. If any one has a quick answer to this question then you must know a little bit about MATROX cables so care to enlighten me on how they work?

    I'm ok with a PM or email so this thread isn't too inconvenient.
  3. I believe they emulate a monitor through a USB port to the matrox device which then gets output to a second screen, while it will work USB is extremely bandwidth limited, no expect to watch stuff like HD movies, or play video games on it. simply not enough bandwidth
  4. Best answer
    Some of the Matrox video cards are special. They have one or two LFH-60 connectors on them. An LFH-60 carries the video signals for two displays (LFH-60 to 2 x DVI-I or LFH-60 to 2 x VGA depending on the Breakout / Splitter Cable used).
  5. Best answer selected by no_regretsYSL.
  6. This topic has been closed by Mousemonkey
Ask a new question

Read More

Graphics Cards Dual Monitors VGA Graphics