I am in the market for a new box and want to run Fedora on it dual-headed. I have recently had a very hard time getting an older machine to run dual head with a matrox g450 which is sitting on my desktop right now.

What hardware do I get that will run dual head straight out of the box??

Riley

February 8, 2008

Hi RileyTheWiley


Well that is a fairly broad question.

I have successfully run dual display adapters on a large range Pentium III platforms.

I have found that the key to success is to make sure that you install two (or more) display adapters with the same amount of on board memory. This is crucial because the bit depth supported for each display is the minimum bit depth of the two (or more) display adapters. The bit depth being directly determined by the amount of memory on the display card.

eg. using two PCI adapters (same make, model; or different for that matter) one with 4 MB the other with 64 MB. The bit depth for the display on both connected monitors is limited to the bit depth associated with the 4MB display card.

So it pays to get two similar display cards, both with the same amount of on board RAM; or use two display cards with differing amounts of RAM and be prepared to use the maximum bit depth on the card with the least amount of RAM.

With XFree86 you can mix an match PCI and AGP adapters in most cases.
Though with some systems (eg. old HP PIII retail PC boxes) that have integrated AGP adpaters, I've experienced some problems.

I guess i really comes down to your display requirements.
ie. the resolution, and colour depth that you require on the displays;
together with other performance factors; and your intented application (eg. Games, status displays, X desktops, etc)

As far as auto configuration goes (ie. out of the box) I've found that it is often better to simply perform a disto install with a single adapter; shutdown the PC; install the additional adapters and connect the monitors; then manually edit the Xwindows scripts.

On early distros some of the Multihead configuration tools are not the best.


To determine the brands and models of cards supported check out the
www page of the XWindows implementation that you are using, and the man pages in your distro. There is also an excellent linux HowTo on the www
that you can find that will lead out by the hand to setup a simple multihead environment.

I hope that helps.

Chris

RTW --
I have several systems running both AGP and PCIe with dual dislays.
I only use NVidia GPU cards, the new NVidia driver install will even configure the system for you. You will likely need all the kernel dev rpm loaded if NVidia needs to build a driver to match your kernel. The drivers are available from nvidia.com Far superior to the native dual drivers.

That is about as close as you can get to out of the box with Linux. HTH

Many thanks to you both. I did get a linux box running dual head but noticed one monitor would not go above 800*600. That is probably due to the memory sizing issue.

I will look for a system with an NVidia card.

Riley