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