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Looking for a solution to get three monitors wired in…

So, as my job lately required me to have a lot of windows open to look at, and even my two monitors setup started to feel cluttered, today I decided to invest some of the money I got for my last job to get a new monitor. I decided to get a 20” wide Samsung monitor. Not a bad choice as the monitor is quite nice and seems to blend well with the other two monitors I have.

I haven’t tried to set Xorg correctly yet, that I’ll do tomorrow, as I mounted it in quite late. I also added in an MGA (Mystique) card to see if I can wire in three monitors on Enterprise.

I haven’t investigated too much, but as far as I could see from the results of messing with xorg.conf, the Radeon 9250 does not get by default 1680×1050 which is the resolution of the monitor (if I can get it to run at 1680×1024 would also be nice to me). Also when I set the Virtual size parameter to 4260×1024, I get corrupted images.

Trying to start the mga head with any resolution seem to get me a “not enough video memory”, which might actually be comprehensible, considering the age of the card.

Now, if anybody has an idea how to get three monitors wired in… an option would be to get a Dual-Link DVI capable card, but the cheapest AGP card I can find is a 7600GT from nVidia (which is quite good, I’m sure nVidia would actually get multi-monitor working fine, it was one thing I never had problems using with it), but it costs €100, and I’m planning to change computer next month or the one afterward for a faster box, and I’m not sure if it’s a nice idea to get a new videocard for it now.

Well, I’m not in a hurry, the third monitor will be connected to the laptop tomorrow, so it will not be wasted even if I don’t change the card right away, and I might actually find a solution for the problem with mga.

At any rate, if anybody has a Dual-link DVI (+VGA, or anyway something that could run 3 heads) capable card that is not being used, and want to help me in any way, I’d say this time I’d accept 😉 Though I might actually get the new card, after all I am going to sell the computer when I get a new one, so I might just count in the card 🙂

Comments 6
  1. You have me confused here….I thought the dual-link DVI interface only links two one monitor. Having two of these interfaces on the card still only supports two monitors, or am I wrong?Even though the nvidia cards have three outputs (the TV-OUT being the third) they used to share one of the DAQ, which is probably still the case. For that reason it was not possible two run two monitors + the TV simultanously. At least I couldn’t get it to work on a GT6600.For 3 monitors I thought the only option is to plug in a second graphics card into your PC. If you have an old PCI graphics card lying around that might do the trick in case you have a motherboard with only one graphics-card-slot.**) Note that there are off course professional graphics cards that do support more then 2 monitors, but they are probably way more expensive.

  2. As far as I remember, most MGAs had 4MB of VRAM. That could be the cause of your “not enough video memory” problem.To run 1680 x 1050 at 24bpp (3 bytes per pixel) or 32bpp (4 bytes per pixel), you need 8MB of VRAM.1680 * 1050 * 3 = 5292000 bytes1680 * 1050 * 4 = 7056000 bytes

  3. I’m afraid you’re right bandigarf. I’ll see if I have better luck with some S3Trio but I doubt so :/moesaji, a Dual-Link DVi port can be divided into two DVI-D ports, to connect two (digital) monitors at once. With a Dual-Link DVI port and a VGA port, the card would support three monitors just fine, in theory. The 7600GT series should do that. Then I’d just have a cable like “this”:amazon:B000X7TNK8 (which doesn’t ship in Italy, of course), and get the two monitors with DVi connected to that…

  4. Thanks I learned something again….But that does mean that you have to be careful when ordering the card as not all suppliers have their details correct.I have an leadtek GT6600 lying idle here as it made too much noise for my taste. It unfortunately doesn’t have dual-dvi, but some other GT6600 cards do support dual-dvi:…Note that you must be able to find a 7600GT way cheaper then 100 euro. has the AGP-version for GBP43 and free shipping (within the UK),

  5. Actually I was forgetting one thing :/ Dual-DVI arrives usually at 2560×1600, while my two DVI monitors would have 1280+1680 = 2960 pixels of width, which is going to be 400 pixels wider.The two 17″ monitors could fit together in a Dual-link DVI port, but one of them is VGA-only (and as far as I can see, I can’t share a Dual-Link DVI-I with a VGA and a DVI monitor).So I think I’ll keep a PCI VGA card for the third monitor. Right now I switched the MGA with a 3D Blaster Banshee (3Dfx), which has 16MB of video ram and should work fine at 1280×1024. As I can’t get xinerama to view it as a single desktop, I’m going to make it an extra seat, with dwm most likely, without mouse… useful when I need to keep an eye on logs and similar.

  6. You may want to look at Matrox DualHead2Go or TripleHead2Go. These are completely hardware-based. They require Windows for configuration but will work fine with Linux afterwards.

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