Here we have the R300 system block
diagram with all the major engines represented. As you
can see, ATi has revamped it's HyperZ Compression engine
which can offer nearly a 10:1 ratio in savings in total
memory bandwidth.
SmoothVision
2.0 - Now with gamma correction and Anisotropic Filtering
for free
In addition, ATi has improved on their
SmoothVision engine for Anti-Aliasing and Anisotropic
Filtering. SmoothVision 2.0 utilizes a 2X, 4X or 6X
Multi-Sample AA approach but also includes a new gamma
correction technique. In addition to sampling jagged
image pixels in a given scene, the Radeon 9700's
SmoothVision engine also adjusts gamma correction for those
samples when they are applied and it determines the best
color uniformity for each pixel. ATi claims this will
produce superior AA image quality compared to anything on
the market.
Finally, ATi has brought forward the
same great anisotropic filtering techniques from their
Radeon 8500 line, In addition the Radeon 9700 Pro has
the ability to drive Trilinear Anisotripic Filtering .
Now however, up to 64 tap aniso filtering can supposedly be
enabled with little or no performance penalty. Again,
this is another claim that we'll just have to look into with
our benchmarks that follow.
256 Bit Memory Controller - Bandwidth rules
None of the Radeon9700's
special features could be utilized fully without the
capabilities of this component in the R300 architecture.
Memory bandwidth continues to be the main limiting factor
for achieving 3D Graphics performance. With the
limitations on modern memory technology and memory
controller latency, as clock speeds scale, ATi decided to
design the R300 with "fatter pipes". Current
generation GPUs have 128 bit memory interfaces running at
650MHz. The Radeon 9700 Pro and it's R300 VPU has a
256 bit memory interface running at roughly that same speed.
You guessed it, twice the bus width affords twice the
bandwidth, clock for clock.
DX9 Shader Units - Ahead of the curve
The Radeon 9700 has
version 2.0 Programmable Pixel and Vertex Shaders.
These are next generation programmable engines that now have
floating point precision and can support hundreds even
thousands more instructions for more complex and realistic
renderings.
Real-time Fur Rendered With SmartShader 2.0
Click image for full view
The Radeon 9700 will be
able to take full advantage of the enhancement brought forth
by the DX9 Shader Language, once developers have begun to
release game titles that take advantage of the new API.
Incidentally, DirectX 9 is rumored to be coming out in the
October time frame, right around corner.
The VPE - An ATi strength from way back
To close out our quick
take on the Radeon 9700 Pro's architecture, we have a look
at the card's Video Processing Engine. Incorporated in
the R300 VPU is ATi's legacy of well rounded digital video
processing prowess. Hardware support for motion
compensation, IDCT (inverse discrete cosine transform),
scaling and adaptive de-interlacing are all still very much
a part of the architecture. In addition, ATi added the
"FullStream" de-blocking filter, that
we told you about here back in July. This feature
allows for the smoothing over of pixels during video
playback from lower quality sources. The result is a
significantly clearer image during playback. With the
Radeon 9700 Pro board we received, ATi bundled an enhanced
version of the RealOne Player that supports FullStream.
We've experienced the effect first hand and it does make
quite an improvement.
On the DVD playback front,
we are of the opinion around the HotHardware Lab that ATi's
DVD playback has always been a notch or two above anything
on the market. The Radeon 9700 Pro was more of the
same for us, displaying some of the cleanest DVD output on
our VGA monitor, that we have ever seen.
A
note on desktop image quality and The Radeon 9700 Pro's
Display Interface:
Finally, the display interface of the R300
VPU and Radeon 9700 Pro we tested, has been goosed up a
notch or two as well, with dual 400MHz DACs for super sharp
output at high resolution. We were able to crank the
resolution on our 22" Mitsubishi monitor all the way up to
1600X1200 at 85Hz with excellent clarity. Desktop
color saturation and sharpness was not quite up to Matrox
Parhelia levels for us. However, it was completely
acceptable at high resolutions and drove slightly better
desktop image quality than what we have seen on Radeon 8500
of GeForce 4 boards.
