SGI: Hardware

I know this type of question has been asked multiple times but from all my reading I still don't see a clear picture. So here is my very specific question:

The Onyx2 has a DG5-2, so this gives me two 13W3 connectors. If I were to use a single display I would go for a full HD resolution which I know the IR2E is capable of (and then some). I have a GDM90W11 and tested the resolution with that. Result is satisfactory (there is a picture) but the display is worn out so I would not call that crystal clear. So I figured why not use the 24" SUN TFT I have. It has a DVI and a 13W3 input. So I figured I need to hook up to the 13W3 since the DVI is digital only. I used a straight through SUN cable as well as SGI cable. The result was no sync. Since the pins for sync signal are different between SGI and SUN I said: OK that can happen. I was hoping that it was going to work like my old 20" SUN does but it doesn't. The SUN CRT probably just uses SOG when it can not find any other sync signal that makes sense which is something the TFT is not doing. I am just guessing here, though. My next test step was to use a original SGI 13W3 to VGA cable. That way I was sure the sync signals were now on the correct pins for the average PC monitor. I then connected that to a SUN VGA to 13W3 adapter. It came with the raptor graphics in my SUN E450 card which has a VGA output and is normally intended to hook up that SUN to a 13W3 monitor. This gave me a picture but no matter how hard I tried adjusting the TFT I never got to a picture that was even near the quality I get when hooking up a Fuel to the DVI. Even though I use the native resolution it remains rather blurred and needs a lot of shifting around to fit the monitor properly. If I let the monitor auto-adjust it screws up the picture even more.

So after this long and sad story here is the question (finally):

Is this something specific to that SUN display or the SUN adapter? I mean can I buy a standard 24" PC Display, use the original SGI 13W3 to VGA cable and expect to get a clear and nice picture? I know there is different qualities of PC monitors and probably not any one will do, so the answer might be: "depends on the monitor", but given I choose the right one can I expect to get a decent picture? What I mean is, has anybody been there and can confirm it is worthwhile to buy and attach a 24" TFT to an analogue output?

If the answer is yes. Can I run two of them? I know it depends on frame buffer size and bandwidth. So has anybody hooked up two 1920 x 1200 or 1920 x 1080 displays to their Onyx2?

I've used a DELL 2407WFP (24", 1920x1200) panel on my Onyx2. Works nicely, but to get an acceptable picture quality at such high resolutions you need quality cabling and minimize the number of plugs and contacts in the signal path. So avoid 13W3-HD15 converts and PC VGA cables, but use a quality cable with a 13W3 plug on one end and a HD15 on the other end.

A DG5-2 has too little bandwidth to run two panels at 1920x1200 @ 60Hz. You can fiddle with the refresh rate to lower the bandwidth requirements but your panel and/or eyes may not appreciate the results. I believe a DG5-2 will do twice 1920x1200 @ 56Hz, but the 2407WFP didn't like it. I will probably get myself a pair of 1920x1080 panels some day, but have been too busy with other projects recently.

Ironically, a V12 with DCD will do twice 1920x1200@60Hz.

Any SUN 13w3-producing or -consuming device (like a gfx card or monitor), although some adapters "adapt" for this. For instance, I got a converter adapter with some dip switches on it from reputable.com years ago to let a standard PC monitor connect to a SUN system.


As long as the monitor supports SOG and the resolutions the SGI can pump out, yes.


You'll have to do the math or just use ircombine to tell you what's a valid combination. A single pipe IR probably doesn't support 2x 1900x1200 at a decent refresh -- that's a lot of pixels/sec.

With an LCD you don't need a decent refresh, though. I always ran my 1600sw at 50 hz to try to take a little load off the O2. You couldn't tell the difference. For gaming you'd want your inputs to display faster but for watching, you're not going to notice any improvement over 30 hz.

@zuluchas: I kind of think this SOG thing is a myth. It is true some (if not all, I have a list at home) of the SGIs will output SOG. But I am convinced that all the machines I have will also offer H-sync and V-sync on certain pins. The SOG myth probably came up like this: People hooked up VGA displays to SGIs with SUN adapter cables. Since SUN 13W3 will output sync on different pins than SGI (and output composite sync) the display will not be able to synchronise on that. So a SOG capable display will resort to SOG as the only sync signal it gets where it expects it and hence only a SOG capable monitor will display something. However: If you have a proper SGI 13W3 to VGA cable I am convinced that also a non SOG display will do just fine. The above goes for Indigo and newer. I don't know about older systems. I totally agree that two displays at 1920 x 1200 might be too much and I need to do some math / ask ircombine.

@jan-jaap: That was my question. So what you are saying is: If the monitor can sync it and you have high-end cabling with as little connectors as possible a sharp 1920 x 1200 is possible. Good. Since the more common displays today tend to have 1920 x 1080 that would be a good option since it saves money and bandwidth.

@hamei: I totally agree. Most modern TFT should do 50Hz and 60Hz as a minimum. Since flicker is not an issue I might as well go for 50Hz to save bandwidth.

Has someone hooked up a 1600SW through a multilink adapter? That would be a nice option, too. Even if it's only 1600 x 1024. But it means 13W3 to VGA, VGA to DVI. So again not one single highend cable. I have never seen 13W3 to DVI (analog)...

Don't forget 12-bit IR graphics and look for IPS panels
viewtopic.php?f=3&t=16723203&p=7321620

I can echo jan-jaap's success using a Dell 2407WFP with IR. Ditto for a Dell 1800FP and an NEC 1860NX <both at 1280x1024_60>.

As far as sync-on-green and IR go, it looks like it might be possible to change IR sync output. I haven't had a need to try it out, but ircombine includes a method to modify the default setting of composite sync on green. The ircombine settings were probably intended for use with Barco/high-end projector systems and-or video monitors rather than consumer LCD panels, but might be worth a try if you have sync-on-green issues:
See the Video Format Combiner Tutorial in the Onyx2 Deskside Owner's Guide or the the ircombine man page for additional info