The
differences between the GX2 and standard graphics
products become more evident when looking at the
card itself. On first look the product is surprisingly
barren as the image below shows. Compared to how
well packed recent high end cards have been this
is quite a change. The top surface of the card is
rather bland looking and other than the large cooler
the only item of note is the 6pin power connector
which is required for operation.
Tipping
the card on its side reveals a little more and its
easy to see that the GX2 is actually two PCB’s
bolted together.
There
is no power connector on the 2nd PCB however there
is a cooler which is identical to the 1st PCB’s.
To the left of the cooler the connector which passes
data between the two cores can be seen.
The
cores on the 7950 GX2 are 90nm chips (278M transistors)
and feature 24 pixel pipelines and 8 vertex shader
units each. (That’s 48 Pixel and 16vertex
in total). Each core is clocked at 500mhz which
is slightly higher than the 7900GT at 450mhz however
below the 7900GTX’s 650mhz.
Like
the front of the top PCB the rear of the card is
very sparsely populated with the only part of note
being along the top edge. Along this edge you can
see the SLI connector which allows you to attach
the card to another GX2 in order to take advantage
of Quad SLI when it becomes available.
By
turning the card lengthways it is possible to see
the output connectors available on the GX2, the
available outputs are dual DVI and HDTV-out. A dongle
can also be attached to provide S-Video, Composite
or YPrPb output.
It wouldn’t
be unreasonable to think that the GX2 would be a
huge card however through some excellent engineering
which has enabled to keep power and thermal requirements
down.
Nvidia
have been able to keep the size of the card identical
to the GTX and X1900XT. The image below shows the
GX2 alongside these other products.
From
an external point of view the above images show
the GX2 in it’s entirety however it is also
interesting to take a look at how the cores communicate
with each other and the memory.
As shown,
each core has its own 512mb of GDDR3 (2x256bit memory
busses), the two cores can communicate with each
other and with the PCIe switch however only core
1 provides the outputs to your display hardware.
As with other multi card solutions when running
in dual GPU mode only one display can be enabled,
this display has resolutions up to 2560x1600 available
to it.
Finally
it is worth noting that all of the standard features
are available on the 7950 GX2 such as Purevideo,
Shader Model 3 and NVIDIA’s numerous 3d image
technologies (e.g. Transparency Adaptive AA).
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