Digital video (DVI-D) on the Igel-532 X-Terminals

The Igel-532 Premium X-terminals come only with an analog VGA video output. We wanted to drive our new ViewSonic VP211b monitors with a digital signal (the analog signal caused problems, e.g. shadows).

So we investigated putting PCI graphics cards into the Igel. We tried two:

Sapphire Radeon 7000 PCI

This is the second card we tried. We bought the Sapphire Radeon 7000 PCI with 32MB, put it in an open Igel, and it worked at 1600x1200 without needing to do any configuration or software work (the Radeon driver is already included in the Igel firmware). We have not done any power measurements yet, but it appears to produce similar amounts of heat as the G450.

We noticed one problem when we closed the case: the cooler of the graphics card touches the case a little bit; this would actually be great, because it would improve the cooling (better heat transfer to the case). However, the case exerts a little inwards pressure on the card, and for this particular setup, a little bit of inwards pressure turns off the DVI-D output temporarily (D-SUB output continues to work; we have not tested DVI-A); this was probably specific to the card or the Igel box, as we did not have this problem with other Sapphire Radeon 7000s in other Igel-532 Premiums. We finally got the thing to work by wedging something between the cover and the main frame of the case, so that the cover bends away from the graphics card.

It may be a good idea to buy a Radeon 7000 card with a lower cooler; judging from the pictures, the PowerColor Radeon 7000 PCI might be such a card.

See also the caveats about power consumption and RAM requirements below.

In the meantime we also got a 1920x1200 display, and we got it to work with the Radeon 7000. However, the Igel Firmware does not support this directly, so we had to use a different XF86Config file; essentially I just changed the "Modes" and "Virtual" lines in Subsection "Display" of Section "Screen".

Matrox G450 PCI

The first card we tried was a Matrox G450 PCI video card with a DVI output. We put it in the Igel, and, after some playing around, we got it to run and provide 1600x1200 resolution.

Caution: Note that Matrox writes in their manual that the G450 can only do 1280x1024 when outputting on DVI-D, and we had to use a special mode to get at 1600x1200. This mode does not necessarily work with every G450 or every display, so do this at your own risk.

Caution 2: The Igel consumes about 8W-9W more with the Matrox than without it (24.4W instead of 15.8W for an 800MHz Igel), resulting in more heat, and requiring good cooling. Ours have not burned down yet, but be aware of the issue.

Overall, we now have five combos of Igel-532 Premium, Matrox G450PCI, and Viewsonic VP211b, and they all have been working for 7-10 months (including a summer). However, about half of the Igels we tried did not work with the G450 right from the start (various failure modes).

Also, we found that the X-terminals need more RAM than the built-in 64MB in order to be useful (otherwise they run out of memory soon, resulting in various failure modes). 128MB seem to be enough.

Ok, here's what you need:

Here's the mode:
Modeline "mymode" 122.00  1600 1688 1780 1880  1200 1201 1204 1250 +hsync +vsync
The problem that the G450 has with high resolution modes seems to be the dot clock (122MHz in this mode; it did not work with 135MHz). You can reduce the dotclock further if you have problems; at some point your vertical refressh rate will be too low. To reduce the dotclock without reducing the vertical refresh rate, you can reduce the retrace times (i.e., the numbers between 1600 and 1880 for the horizontal part, and between 1200 and 1250 for the vertical part). At some point the monitor will no longer recognize the signal, but I feel that there is quite a bit of room left for reducing the dot-clock.

Old article: High resolutions on the Igel-532 X-Terminals (for old firmware)

Anton Ertl