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Untitled Document
Introduction
The past few months have been quite tough for reviewers as a whole, with both
nVidia and ATi deciding to launch their next generation technologies at almost
identical times. This means there is a lot of information being bantered around
and a lot to take in and conclude from. It's nice to see a card that is not
just another speed bump but this time we've had our work cut out. This article
is part 1 of 2, focusing on the technology changes as we move to R420 and NV40.
We have tried to summarise these into a digestible format, analysing the facts
and hopefully presenting our conclusions in a simple way to understand.
The Architecture
The most notable and most talked about change in architecture for both generations,
is that of pipelines. nVidia have taken the leap from 4 pixel pipelines to 16
pixel pipelines, ATi making a similar jump from 8 to 16. On top of this, they
have both moved to 6 vertex shaders.
Joining the 9600, ATi have finally bought the rest of their range forward from
a 150nm fabrication process to 130nm, something nVidia did for the NV3x generation.
Both have decided to use the new, and in effect faster, GDDR3 memory modules;
this allows potentially higher clock frequencies due to the GDDR3's low power
design which results in lower heat dissipation requirements. So for GDDR3 voltage
drops from 2.5v to 1.8v and permits the removal of terminating resistors.
Encoding and decoding of MPEG 1,2,4 and WMV9 video is new to nVidia but has
been present in ATi cards since R300. Both are apparantly programmable, but
the solution nVidia offers, involves a rather large chunk of the die which ATi
makes use of the pixel shaders. We won't be able to comment on which is better
until we test it in more detail, but I would be inclined to think nVidias solution
is superior.
Power & Heat
Power and heat have been greatly talked about with these products. As you may
have heard, NV40 requires two molex style connectors directly to the card. This
has raised all sorts of questions about heat output, cooling, and power supply
requirements. R420 on the other hand has almost exactly the same power requirements
as a 9800XT while performing at a considerably faster speed. We put this to
the test, in this article here.
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