Three monitor DVI setup: Two SLI PCI-E cards or single Matrox Quad card?

[ss6nn1]

Which would be better?

Two GeForce7 SLI PCI-E cards that support Dual DVI or this Matrox PCI-E
card that supports Four DVI outputs:
http://www.matrox.com/graphics/corp/financial/products/qidlp.cfm

Each monitor will run at 1600x1200

No gaming on this workstation, but MPEG2 decoding most of the time
(Digital Terrestrial TV)

The advantage of having two GeForce cards instead of the Matrox card
would be that the GeForce has built-in support for "PureVideo" i.e.
MPEG2 decoding which reduces the load on the CPU and the Matrox card
doesn't, correct?

 

[Htnakirs]

Are you sure that, when used in SLI mode, all the four DVI outputs are
available? My guess is NO.
Besides the Purevideo, you also need to consider the speed of the
cards. My guess is that the dual Geforces would be better than the
single Matrox.

 

[Paul]

Which would be better?

Two GeForce7 SLI PCI-E cards that support Dual DVI or this Matrox PCI-E
card that supports Four DVI outputs:
http://www.matrox.com/graphics/corp/financial/products/qidlp.cfm

Each monitor will run at 1600x1200

No gaming on this workstation, but MPEG2 decoding most of the time
(Digital Terrestrial TV)

The advantage of having two GeForce cards instead of the Matrox card
would be that the GeForce has built-in support for "PureVideo" i.e.
MPEG2 decoding which reduces the load on the CPU and the Matrox card
doesn't, correct?

The Matrox card with the PCI Express x16 interface on it
would be a better choice than the Matrox PCI version. At
least the I/O would not be a bottleneck. All modern video
cards have IDCT, so the Matrox does provide at least
that acceleration feature.

Purevideo, on the other hand, is hard to understand, because
the only info you have to go on, is the second-hand info
from review sites.

When two SLI cards have SLI enabled, only _one_ output
connector works. When SLI is disabled, and the two
cards function independently, you can drive four monitors
with the two VGA/DVI-I connectors on each card. At least
that is the info I've seen to date. I don't know if the
rules for SLI operation have been changed lately or not.

You would not need super-powerful Nvidia cards for movies. You
could use 7600GT for example. (7600GT seems to have a pretty
high GPU clock, which maybe is contributing to the processing
rate. Draws 67W max. You probably would not be driving both
of them to max heat output at the same time.) But the amount
of offloading noted here, is not that great. This is for HD.
There have been previous articles reviewing the improvement
for non-HD.

http://www.anandtech.com/video/showdoc.aspx?i=2798&p=3

And here is an Nvidia page that lists support for features:

http://www.nvidia.com/page/purevideo_support.html

MPEG-2 decode is mentioned on that page, and it looks like
more of their video cards support that. If you wanted a
quiet box, then there will be compromises between performance
and fan noise or heat.

And if you were thinking of getting a video card with
no fan on it, the temps can rise quite high on cards like
that, and a crashing video card is no good to anyone:

http://hardwarezone.com/articles/view.php?id=1856&cid=3&pg=9

You might find more info on the subject, on a forum like this:

http://www.avsforum.com/avs-vb/showthread.php?p=8067688&highlight=purevideo#post8067688

(MSI and others are preparing to ship video cards with HDCP
on them. Which would be a bit of futureproofing. The 7600GT
on the left, is available now on Newegg. This might save you
having to buy another pair of cards in the future.)

http://www.msicomputer.com/msiforms2/HDCP.asp
http://www.newegg.com/Product/Product.asp?Item=N82E16814127217

Paul

 

[WindsorFox]

When SLI is disabled, and the two
cards function independently, you can drive four monitors
with the two VGA/DVI-I connectors on each card. At least
that is the info I've seen to date. I don't know if the
rules for SLI operation have been changed lately or not.

Are you sure, as in have you tried this? When I set up my current
system with SLi my monitors did not work in then 2nd card, I had to move
them to the 1st card to get any video, leading me to believe that in
non-SLi mode the 2nd card is off. I never tried putting any monitors on
the second card with the 2 installed on the 1st card at the same time so
I can't say factually one way or the other. I can back up the fact that
only one monitor works in SLi mode which kind of blows. I just took my
old parts and put them in a Shuttle BB and perched it atop the new
machine and when in SLi I can switch the blank monitor to the analogue
input and use the Shuttle to surf my game hints, cheats and Team Speak.

 

[Don Freeman]

Are you sure, as in have you tried this? When I set up my current
system with SLi my monitors did not work in then 2nd card, I had to move
them to the 1st card to get any video, leading me to believe that in
non-SLi mode the 2nd card is off.

..
Maybe that is motherboard dependant but ASUS claims that their A8N-SLI
motherboard can drive 4 monitors simultaneous when the 2 video cards are not
in SLI mode.

 

[Paul]

.
Maybe that is motherboard dependant but ASUS claims that their A8N-SLI
motherboard can drive 4 monitors simultaneous when the 2 video cards are not
in SLI mode.

If you don't like my answer, then get the answer straight from
Nvidia.

http://www.slizone.com/page/slizone_faq.html#s8b

"How many monitors are supported when running in SLI mode?

When in multi-GPU mode, SLI currently supports one monitor.
When in single-GPU mode, users have the ability to use up to
four monitors using NVIDIA® nView® multi-display technology
and Windows XP Dualview."

HTH,
Paul

 

[ss6nn1]

Maybe that is motherboard dependant but ASUS claims that their A8N-SLI
motherboard can drive 4 monitors simultaneous when the 2 video cards are not
in SLI mode.

Sorry I seem to have thrown everyone into confusion by mentioning SLI.
I originally meant a motherboard with two PCI-E slots and both running
at the same time in non-gaming mode (no SLI).

I think I'll go with two GeForce 6600GT/7600 cards each with Dual DVI
to power the 3 monitors because it's cheaper than the single Matrox
card that supports 4 monitors (~£400/$800 USD).

 

[Don Freeman]

If you don't like my answer, then get the answer straight from
Nvidia.

http://www.slizone.com/page/slizone_faq.html#s8b

"How many monitors are supported when running in SLI mode?

When in multi-GPU mode, SLI currently supports one monitor.
When in single-GPU mode, users have the ability to use up to
four monitors using NVIDIA® nView® multi-display technology
and Windows XP Dualview."

..
Isn't that just what I said?
-Don

 

[Paul]

.
Isn't that just what I said?
-Don

When Nvidia says it, then it is not motherboard maker specific.
It is a function of their current driver and its policies.

Paul

 

[deko]

Two GeForce7 SLI PCI-E cards that support Dual DVI or this Matrox PCI-E

card that supports Four DVI outputs:
http://www.matrox.com/graphics/corp/financial/products/qidlp.cfm

Each monitor will run at 1600x1200

No gaming on this workstation, but MPEG2 decoding most of the time
(Digital Terrestrial TV)

The advantage of having two GeForce cards instead of the Matrox card
would be that the GeForce has built-in support for "PureVideo" i.e.
MPEG2 decoding which reduces the load on the CPU and the Matrox card
doesn't, correct?

I use the AGP QID - supports 4 DVI displays, but I'm happy with 3. The PCI-e
QID is top of the line (assuming you don't need 3D). One of the great things
about these cards is Matrox's display management software. Matrox has been in
the multi-display market for a while and has the best display mgt sfw around,
IMHO. As for video, I play everything on InterVideo WinDVD - looks great, never
had a problem. If you're looking at a PCI-e QID you probably (or should) have a
high-end mobo/proc - why are you worried about CPU load? Display management
software is a more important consideration - and is why I picked Matrox over
nVidia. Matrox has better support, too.