On Sun, 24 Aug 2003 07:44:52 -0400
(Paul) wrote:

In article , Steve
wrote:

Hi,
I'll be buying a 22" Mitsubishi Diamond Pro
http://www.necmitsubishi.com/product....cfm?product_i
d=232&division=MITSUBISHI and am now looking a various cards to
drive this monstrosity. Mitsubishi specs say it can go to 2048 x
1536 @ 86 and my job now is to match it to a card provide the
signal. Although I will probably have the screen set to 2048 x 1536
I figure if the card can do this it will be able to provide viewing
at lower resolutions flicker free.
My needs are to provide clean displays of various large data sets
in
2D, sometimes rotate them in 3D and a little low-tech gaming like
Age of Empires, Sim City. I'm a little confused because cards
advertised with 64 MB, 128 MB, or now 256 MB of memory all claim to
be able to display at resolutions near to my 2048 x 1536 benchmark
so there must be more than aggregate memory that determines ability
to run large monitors at high resolutions.
The Matrox P750 seems to a reliable choice for the job but lacks
some of the fun stuff of say the ATI AIW 9000 Pro or GeForce4 Ti
4600. Will $150-$200 get me a reliable, flicker free card that can
display at high resolutions (that way I can see more of the data
set) or am I asking too much of a card in this price range?
One last question. What is the end result of setting the screen to a

resolution and refresh rate that the card doesn't list? For example,

the monitor mentioned above lists a capability to display 1800 x
1440 @ 92 Hz but the closest a Radeon 9800 Pro comes in terms of its
spec sheet is 1920x1080 @ 120. How would this display on the screen?
Thanks for the help with these questions.

To run at super-high resolution places demands on the video DAC
(digital to analog conversion) on the card. At one time, the DAC was
a separate chip, allowing the best technologies to be selected for the
2D/3D acceleration and for the DAC. Now, the DAC is integrated into
the main chip, so must make do with CMOS for drive.

What you are trying to do, makes demands on the frame buffer (to
source data to the DAC). But, frame buffers now have huge bandwidths,
so that is not particularly a problem. (The tremendous amount of
memory on video cards now is for 3D texturing.)

You will notice, that the products you are looking at, don't display
32bit color, all the way to 2048x1536. This is because the DAC cannot
settle to an accurate voltage value at the frequency required.
That is not a killer issue (unless you are a Photoshop freak).

When the signal comes out of the logic chip, it is filtered by some
PI filters to meet EMI requirements. Depending on the design, some
cards have too much filtering, so the display will lack sharpness
at super-high resolutions. There used to be some web pages, showing
how to remove some of the components on the board, to improve the
sharpness of the display (at the cost of adding more emissions to
the local environment).

High resolution also places demands on the dot clock and sync signals.
Any jitter either interpreted by the monitor, or added by the display
card, degrades pixel resolution. Separate H and V sync signals make
this easier to do (H,V,R,G,B cables).

You should also pay attention to the output connector style and the
cable used with the monitor. To display at 2048x1536, the video
bandwidth is quite high, so the cables and connectors used should
form a perfect transmission line (RF quality connectors).
Unfortunately, many cards and monitors use a VGA connector, and
the connector isn't a perfect match to the line. The best cabling
consists of 5 BNC connectors and coaxial cables, with RF quality
(shielded) connector pins on the connector that mates to the computer.

In this respect, Sun computers have had the right solution for
passing video signals, but other platforms still suffer with
approximations to that. The connector that plugs into the Sun
computer uses coaxial connector pins for the video signals.

The claims that the monitor makers make should also be viewed with
suspicion. Some monitors are not really happy at their highest
resolution setting - the corners of the image will be rounded a bit,
or the display may be wavy near the top or bottom. Running at
2048x1536 places huge demands on the display drive circuitry -
the monitor will run hot, and the HV section of the monitor will
be running full blast.

So, where does this leave you? You really need to do a viewing test,
ideally with the video card you plan on buying. Most of the time
this isn't possible, so even seeing the monitor with some other
video card is still worth while. In particular, when testing the
monitor out, look to see whether the screen can produce a consistent
white color all across the screen - I've noticed large Trinitron
tubes, for example, will be discolored in one corner of the screen,
or the image intensity will not be a constant across the full screen.

With respect to some of your resolution questions, think about
the "square pixel" problem. The display you've selected has a
4:3 aspect ratio, and neither 1800x1440 nor 1920x1080 will
result in a displayed circle looking circular (unless you set
the monitor width/height to not use the full screen). The same
is true of buying a 16:9 display - you need to find a display card
that has output modes suitable for that aspect ratio. You can always
adjust the width or height of the screen at the monitor, but
circles won't be circular without losing some screen real estate.

The Matrox cards still have the reputation of having the best
image quality, so in that sense you are probably looking at the
right company for this application. But, their software drivers
always leave a bit to be desired, in terms of getting accurate
colors to the screen and the like.

If you do go ahead with this plan, I think you'll find you spend
most of your time at 1600x1200, as the monitor will run cooler,
will have less image distortion, and text will still be readable
at that resolution. You can switch up to 2048x1536 to look at
color images, but don't expect normal desktop text to be too good
at that same resolution.

Since your monitor has two input connectors, there are games
you can play with two video sources. At work, we used to connect
two computers to one monitor, which allows changing platforms
at the click of a button (and a lot of fumbling with two keyboards
and two mice). You might even use two PCs - one with a good
(but slow) high resolution card for working, and a second PC
set up for gaming.

For the ultimate display resolution, IBM had an LCD product.
Go to ibm.com and search for "T220 Display". It has a resolution
of 3840x2400 and comes with a modified Matrox G200MMS video card.
When IBM first announced a device like this, I think it was
using multiple video cards, but the combined output of the four
display drivers is enough from the Matrox quad-head card. The
T220 display lists for $21000. Note - You cannot play games
with a setup like this, as the video card is PCI based and slow
as molasses.

http://www-1.ibm.com/support/docview...sg1MIGR-4XWF7Y
http://www.matrox.com/mga/products/g200_mms/home.cfm

Just a comment, but the T220 is discontinued--the replacement is the
T221, which has the same specs but is available with a variety of
inputs. Viewsonic has a similar model for around $6000.

IBM also had a 21" LCD model T210 with 2048x1536 native resolution
that's a little cheaper than the QUXGA Viewsonic. The T210 appears to
be discontinued but is still available in the distribution channel.
Iiyama also has a 2048x1536 LCD for a bit more, about the same price as
the Viewsonic.

Have fun,
Paul


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--John
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