Inquiry to Matrox re: 1600x1200x3 - Response not helpful

Post by **wazoo** » 26 Aug 2008, 21:13

I sent off an email to Matrox asking them about support for 3x1600x1200 since they updated the firmware for 3x1680x1050.

Below is the email thread which, IMHO, is less than satisfactory.

I've requested my question be elevated to someone who might have a bit more knowledge on this subject:

=======================
From: Technical Support [mailto:[email protected]]
Sent: Tuesday, August 26, 2008 12:27 PM
To: 'Paul '
Subject: RE: Tech Support - United States - Other - Request ID: 15725

Hi Paul,
Itâ€™s good to know that there is a software solution for Triple Head. However our TH2Go is a hardware solution for TH. To my knowledge 3x1920*1200 exceed the capability of the most recent graphic card.
We are not sure what SoftTH exactly does. Of course you have your choice to try SoftTH.
Thank you.

Zhen X. Du
Matrox Technical Support Rep.
Tech Support Tel: 514-685-0270
Office Hour: 9h00-17h00 EST
________________________________________
From: Paul
Sent: Monday, August 25, 2008 7:04 PM
To: [email protected]; [email protected]
Subject: RE: Tech Support - United States - Other - Request ID: 15725

Zhen,

Iâ€™m a bit confused by your response. Are you saying it is not physically *possible* to do 4800x1200??

If so, how do you explain that this is routinely done running the *free* triplehead software application SoftTH? In fact, MANY SoftTH users run at 1920x1200x3.

Your thoughts?

Paul

From: Technical Support [mailto:[email protected]]
Sent: Monday, August 25, 2008 12:55 PM
To: [email protected]
Subject: RE: Tech Support - United States - Other - Request ID: 15725

Hi Paul,
Our GXM products work like a plug and play monitor and its capability heavily depends on the graphic card.
Thanks to some recent models of graphic cards, some triple wide resolutions became available. That is because the graphic cards can do a higher resolution.
However 3x1600x1200 is greater than 3x1608*1050, and so far we donâ€™t know what card can do that. So 3x1600*1200 is not supported.
Thank you.

Regards,
Zhen X. Du
Matrox Technical Support Rep.
Tech Support Tel: 514-685-0270
Office Hour: 9h00-17h00 EST
________________________________________
ORIGINAL MESSAGE:

Message: Hello, I see that you recently updated the firmware to allow 1680x1050x3 for WS triplehead gaming. Many of us use 1600x1200x3 and have been forced to use 1280x1024x3 due to the firmware limitation of the TH2Go. Is there any chance an update will allow for this resolution? Thank you.

kodex · Post by **kodex** » 26 Aug 2008, 21:38

Obviously this guy's job is to give canned answers. You need to talk to an engineer, or at least someone who can do that for you. Why not send a PM to that Matrox employee that posts here?

Post by **skipclarke** » 27 Aug 2008, 01:19

I have pointed this thread out to one of my contacts at Matrox. No promises, but this should get it into the right hands.

skeeder · Post by **skeeder** » 27 Aug 2008, 01:39

1680x1050 is less pixels. But honestly I don't see why its not doable.

Post by **BHawthorne** » 27 Aug 2008, 03:19

1680x1050 is less pixels. But honestly I don't see why its not doable.

The CSR that replied needs to learn a bit more about surround screen gaming. The question that needs to be put forth is...3x1600x1200...does that exceed the bandwidth of Dual-Link DVI and the bandwidth within the chip used in the TH2G D? If all is good on both of those issues, it's in Matrox's ballpark to either support it or not.

Then again, I'd love to be able to use 3x1920x1080 or 3x1920x1200. Makes me ponder DisplayPort in future cards and a new Matrox box based on it for 3x1920x1200. With DisplayPort, the port is small enough you could put 3 video outs on the back of the card and just do it all via the video card if designed correctly on a hardware and display driver level.

Anyone have the numbers for max pixel limit on Dual-Link DVI? I'm seeing a bunch of 3840x1200 (9,216,000 pixels) references for dual-link dvi limit on google. That would mean 3x1920x1200 was plausiable at least through the cable. The chip Matrox uses in the TH2G D is a whole other variable though.

3x1680x1050 = 5,292,000 pixels
3x1600x1200 = 5,760,000 pixels

3x1920x1080 = 6,220,800 pixels
3x1920x1200 = 6,912,000 pixels

2x2560x1600 = 8,000,000 pixels
3x2560x1600 = 12,000,000 pixels

Mesh · Post by **Mesh** » 27 Aug 2008, 03:58

Maybe 3x1920x1080i would work? since technically interlacing should half the bandwidth per screen or something.

Providing the receiving screen has a proper deinterlacer, it should be almost indistinguishable from 1080p.

Dem Pyros · Post by **Dem Pyros** » 27 Aug 2008, 04:09

Maybe 3x1920x1080i would work? since technically interlacing should half the bandwidth per screen or something.

Providing the receiving screen has a proper deinterlacer, it should be almost indistinguishable from 1080p.

Not exactly. The problem with that is you would be pushing less frames.

For video and TV signal, that's not necessarily a bad thing, as most movies are shot at 24fps anyhow.

The problem is, with interlaced video you get only thirty frames (sixty frames delivered, each one with either odd or even scan lines). This isn't a problem for film, but for video games you would see a much more choppy image.

The other problem with interlaced is I don't think that the graphics card, when outputting a resolution could do interlaced unless it was an HD resolution. Otherwise that would most likely just be 30hz, and then the graphics card would be outputting the same amount of information, just less per second (but nonetheless the same amount per frame).

Mesh · Post by **Mesh** » 27 Aug 2008, 11:26

Sports and stuff get played at 1080i and I'm sure many people can see a problem with it. And those weren't shot in 24fps.

Aren't you mixing up 3:2 pulldown and interlacing? I don't think they're the same thing.

And even if the frames are a bit slow, slow beats nothing no?

Dem Pyros · Post by **Dem Pyros** » 27 Aug 2008, 12:49

Sports and stuff get played at 1080i and I'm sure many people can see a problem with it. And those weren't shot in 24fps.

Aren't you mixing up 3:2 pulldown and interlacing? I don't think they're the same thing.

And even if the frames are a bit slow, slow beats nothing no?

I don't believe I'm mixing them up, because 3:2 pulldown is a conversion for video shot in 24fps to be played on a television in either interlaced or progressive formats. Interlacing is alternating odd and even field in order to display thirty frames per second, with only half of the information being sent and displayed at a given time.

The big difference between interlaced with film and interlaced with games, is that games don't have the motion blur that film does, and so you need a much higher framerate to achieve the same level of smoothness.

And I don't think slow beats nothing for games, I think SofTH would work much better than an external graphics adapter which only works in interlaced (which, again, I'm not sure most consumer grade LCD monitors can support).

JKeefe · Post by **JKeefe** » 27 Aug 2008, 17:08

The question that needs to be put forth is...3x1600x1200...does that exceed the bandwidth of Dual-Link DVI and the bandwidth within the chip used in the TH2G D? If all is good on both of those issues, it's in Matrox's ballpark to either support it or not.

...

3x1680x1050 = 5,292,000 pixels
3x1600x1200 = 5,760,000 pixels

3x1920x1080 = 6,220,800 pixels
3x1920x1200 = 6,912,000 pixels

2x2560x1600 = 8,000,000 pixels
3x2560x1600 = 12,000,000 pixels

Click here and take a look at the first post by user "Billes" on the page. He states:

The maximum bandwidth of a Dual-link DVI cable is 7.92 Gbit/s

With 48 bits/pixel:

7.92 Gbit / 60 Hz / 48 = 2.75 megapixels.

With 24 bits/pixel:

7.92 Gbit / 60 Hz / 24 = 5.5 megapixels.

This gives us a maximum resolution of 5.5 megapixels to play with when using 24bits/px.

Seeing as:

5040 x 1050 = 5.292 megapixels,

It fits within (although barely) the 5.5 megapixel limit.

When Matrox introduced 5040 x 1050, they actually did so at 57 Hz, using 7.239 Gbit/s of bandwidth.

If you do 5760 x 1200 @ 57 Hz and 24 bits/pixel, you would be using 9.456 Gbit/s, which is way over the bandwidth limit of dual-link DVI. To fit 5760 x 1200 into dual-link DVI, you would need to display the image at a refresh rate of 47 Hz. This is well below the capabilities of most, if not all, LCDs.

BTW, 3840x1200 is definitely not the max dual-link DVI resolution. 3840x1200 @ 60 Hz and 24 bits/pixel uses "only" 6.635 Gbit/s, well below the 7.92 Gbit/s limit. If 3840x1200 were the max dual-link DVI resolution, 5040x1050 would not be possible.

JKeefe · Post by **JKeefe** » 27 Aug 2008, 17:17

Thinking some more about this: 4800x1200 @ 57 Hz looks like it is technically possible.

4800x1200x24x57 = 7.880 Gbit/s
This is just below the 7.92 Gbit/s limit. However, I believe some extra DVI information is contained in "blanking", which I don't fully understand. If anyone can discuss blanking I'd appreciate it.

Post by **wazoo** » 27 Aug 2008, 17:44

Informative post JK. Thanks!

At least 16x12x3 seems (without knowing more about the "overhead" requirments of DVI comms) at least possible.

The Matrox Rep said he was sending my question up the line... so we'll see what they say.....

P-Storm · Post by **P-Storm** » 27 Aug 2008, 18:25

From wikipedia

Maximum clock frequency in single link mode: Capped at 165 MHz (up to 3.96 Gbit/s)
Maximum clock frequency in dual link mode: Limited only by cable quality (up to 7.92 Gbit/s)
Pixels per clock cycle: 1 (single link) or 2 (dual link)
Bits per pixel: 24 (single and dual link) or 48 (dual link only)

Single DVI largest resolution
@60Hz = 2.75 megapixels (including blanking interval)
Practical purposes
1915x1436@60Hz
1854x1483@60Hz
2098x1311@60Hz

I did calculate things so, the Dual link is capable to do 2x more then Single link
1915x1436 = 2749940 pixels = 2,74 megapixels
1854x1483 = 2749482 pixels = 2,74 megapixels
2098x1311 = 2750478 pixels = 2,75 megapixels

2,75*10^6*60Hz = 165.000.000Hz = 165MHz
165MHz * 24bits = 3.96 Gbit
This is right for Single link.

Now the other way around for dual link

3.96*2=7.92Gbit
7.92/24bits = 330MHz
330MHz/60Hz = 5.5 megapixels

3142x2357 is good
5238x1050 is also good
5040x1050 is also good, with a bit of space

Now for the DTH2G
5040x1050x57Hzx32bpp=
5040x1050=5.292 megapixels
5.292*57=301.644 MHz

So I don't understand why we must do the 57Hz. If you apply this math then you will see that 5040x1050@60Hz = 317,52MHz

If I knew how big the overhead was...

Post by **wazoo** » 27 Aug 2008, 21:02

Got my reply from George at Matrox. I've spoken with George on the phone before, and he is quite knowledgable about the product:

==============

Hi Paul,

Answering your questions:

Many of us use 1600x1200x3 and have been forced to use 1280x1024x3 due to the firmware limitation of the TH2Go. Is there any chance an update will allow for this resolution?

For the time being, the only supported resolutions are the ones advertised. There is no plan to support 3x1600x1200.

Are you saying it is not physically *possible* to do 4800x1200??
In theory, it is physically possible to do 4800x1200 but it is not always accurate to judge solely by the hardware capabilities.

If so, how do you explain that this is routinely done running the *free* triplehead software application SoftTH? In fact, MANY SoftTH users run at 1920x1200x3. Your thoughts?

SoftTH is using a completely different architecture to achieve this. Although it has some advantages but it has some drawbacks as well. Take for instance the number of titles supported on the TH2Go as opposed to the handful of titles that are supported with the SoftTH solution.

Hope that you all your questions are answered.

Best regards,

George Farah
Senior Technical Support Specialist
Matrox Graphics Inc.

Mark B · Post by **Mark B** » 27 Aug 2008, 22:36

Hi all,

I want to start by thanking everyone for their continued interest in the developments of the Th2Go product line.

All the feedback on this forum is carefully monitored and being taken into consideration by both our engineers and marketing teams.

There is nothing more valuable than a group of dedicated customers voicing their desires and opinions for your product. It's an excellent means for us to keep our finger on the pulse of what you guys want.

TRUST ME -- WE ARE LISTENING :)

With regards to a 1600x1200 resolution, I think JKeefe's response earlier in this thread was quite informative for you guys. Resolution limitations don't exist "by Matrox's design". I.e. our intention is not to have our users suffering with res caps. There are limitations in the DL-DVI bandwidth and in the method cards currently communicate with monitors. This is not to say that larger resolutions can't be considerations as hardware develops, but at the moment our officially supported resolutions max at 3x1680x1050.

Comparing SoftTH and TripleHead2Go is also like comparing apples and oranges. Make sure to visit the SoftTH website and learn specifically how the software functions, you will see that the architechture is completely different from TripleHead2Go. Pointing out that SoftTH can do triple-1600x1200 does not mean specifically that TripleHead2Go should also be able to handle this resolution. There are numerous unique factors for Th2Go that need to be taken into consideration.

At this point, what I can say is that we are definitely aware of what you guys want, and we are working to satisfy the demands of the market as efficiently as possible within the technical limitations that present themselves.

We most definitely value your feedback and hope that it continues.

Thanks again,
Mark

Mesh · Post by **Mesh** » 27 Aug 2008, 23:25

I still say 1920x1200x3 is possible, at 24-30fps in progressive it should work. Provided you can make sure the fps doesn't/barely drops, it's fast enough for all but the most touchy purist.

Dem Pyros · Post by **Dem Pyros** » 27 Aug 2008, 23:37

I still say 1920x1200x3 is possible, at 24-30fps in progressive it should work. Provided you can make sure the fps doesn't/barely drops, it's fast enough for all but the most touchy purist.

....I don't know about you, but 30fps is not nearly enough for me to play any shooting game at.

Mesh · Post by **Mesh** » 28 Aug 2008, 00:38

It is if it's constant, I'm not saying 30fps -average- I'm saying 30fps constant.

I doubt you'd be able to tell the difference between 60fps with 30fps average and 30fps fixed.

Heck, Matrox should remove the 'th2g needs firmware to allow resolution x by y @ z' part.

Just let us send whatever res. we'd care to try and split it up in 3 equal parts.

That it's unsupported is fine, but don't put an unnecessary block. Besides, it'll save you support from failed firmware flashes.

Dem Pyros · Post by **Dem Pyros** » 28 Aug 2008, 02:41

It is if it's constant, I'm not saying 30fps -average- I'm saying 30fps constant.

I doubt you'd be able to tell the difference between 60fps with 30fps average and 30fps fixed.

Heck, Matrox should remove the 'th2g needs firmware to allow resolution x by y @ z' part.

Just let us send whatever res. we'd care to try and split it up in 3 equal parts.

That it's unsupported is fine, but don't put an unnecessary block. Besides, it'll save you support from failed firmware flashes.

For video, I doubt it to. For video games, the difference is quite easy to see (for me at least).

Here, download this.

I can tell the difference, I don't know about you.

Mesh · Post by **Mesh** » 28 Aug 2008, 02:58

I've never put it to the test in detail, but I do know the only times fps was low enough for me to notice something was when it went under 20fps or so. And that's including shooters like ut2004.

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