[bjames]

Hi all,  been a while since last posting 

Will the dcd drive 2 monitors at 1920x1200?  (Dual SGI Sony premierPro sdm-232 24”).  The installation manual suggest it’s designed to drive 2 1280x1024 monitors and not 2 HD monitors.  

Also, I assume using dual monitors on the V12 system will result in slower display performance vs using a single HD diaplay…. Is this correct?

Thanks

[Irinikus]

Hi all,  been a while since last posting 

Will the dcd drive 2 monitors at 1920x1200?  (Dual SGI Sony premierPro sdm-232 24”).  The installation manual suggest it’s designed to drive 2 1280x1024 monitors and not 2 HD monitors.  

Also, I assume using dual monitors on the V12 system will result in slower display performance vs using a single HD diaplay…. Is this correct?

Thanks

I don't have any experience with the resolution in question. I don't seem to suffer any performance loss when running a dual display setup on my Tezro (V12 with DCD).

[Raion]

It should drive two display monitors at that resolution, but there's a catch:

Your video memory will be segmented into two 64 meg segments. This basically means that your graphics memory is going to be limited on each frame buffer to 64 megs. This is due to necessary double buffering needed to ensure simultaneous display updating.

Therefore if you want to get the best for your performance, a DCD will hurt a single display.

[Irinikus]

I’ll carry out some extensive testing in this regard.

It’s not cool to game across two screens. So when I’m running the machine in a dual screen mode, I run the likes of Quake III in a windowed mode on one of the two screens, and suffer no apparent performance loss when running it in this way.

I usually run a resolution of 2x1920x1080_60.

[Raion]

It still shouldn't matter because it still needs to split the framebuffer in two; we're talking about 1990s technology. More modern systems didn't do this but back then memory access wasn't as quick; and you only have so many cycles before memory access times were up. I can't think of any other way that this would have worked, fwiw, since we're not dealing with interlacing or other tricks, and there's no way that FPGA set on the board is capable of say, running at 120hz and double buffering from main system memory each screen 120 times a second. What it's basically probably doing is cutting the upper and lower sections in two and treating the two as on big contiguous display to the GPU, and simply splitting the buffer across those screens.

You might not notice performance loss if your application isn't vram constrained, but again I can't see a way that in the late 1990s where dynamic allocation would be allowed without nasty screen tearing.

[ducks]

Yes, this is possible. Made a vfo for the v12 some time ago with reduced blanking so it works with lcd's as well.

https://forums.irixnet.org/thread-1049.html

[bjames]

Thanks guys, as I suspected it makes sense that there would be a performance hit since your passing the gfx to output a total resolution of 3840x1080 across the displays. I have not made my mind up yet on this… actually been thinking about this for the last few years. I may instead put my money towards an processor upgrade to r14 600mhz as the price is almost the same. My end goal is to max the Octane2 out as I have done on my other systems, it’s just taken the most amount of time due to how expensive high end octane2 parts are.

[Raion]

I have been meaning to eventually get a dual head carrier and take the cards off it and take it over to a machine shop to get it measured and redesigned so that we can eventually have them done for others.

On a separate note I know how those plastic grips are very fragile, so what I was thinking of to do that would be to MIG weld a t-handle to each of the carriers

[Irinikus]

@bjames. What do you intend running on your system?

Here's a video I made a while ago showing the DCD performance on my Tezro:

[bjames]

Hi Irinikis

Mainly doing similar to what you shown in the video, using 1 monitor as the main working desktop for 3d and the other monitor to access the OS and 2D applications for editing image maps. This is the workflow I’m used to using on PCs.

I am currently looking at using 2 5:4 aspect ratio monitors instead of the 2 24” screens due to available desktop space. Since I won’t be pushing the resolution too much, now I’m wondering about using an SI card with the V12 gfx since 1 monitor will not require acceleration or GL. The DCD is very expensive. I would also love to find an O2 DCD like yours.