JUNE 2004 MAXIMUM PC 39
date, the cards run within four frames
per second of each other, even with the
water reflections set to the Pixel Shader
2.0 Ultra-High mode instead of the Pixel
Shader 1.3 fallback mode.
We initially had some problems with
Halo on our test NV40. We were getting
scores as low as 22fps, which just isn’t
right. It turns out that our motherboard’s
AGP aperture was improperly set. Once
we adjusted the AGP aperture to half of
our test system’s memory (512MB), the
card performed better, but not as well as
we anticipated. We fully expect that any
kinks with Halo and the GeForce 6800
Ultra will be worked out before the card
ships.So the nVidia card has a slight edge
when volume shaders are involved,
but the ATI card exhibited an equally
slight lead in the rest of our Lab tests.
This means your purchasing decision
will ultimately boil down to those other
factors we said we weren’t going to talk
about: visual quality, feature support,
size, and noise level. Logistically, the
Radeon X800 XT appears to have an
advantage because it’s a single-slot solu-
tion, and requires only a single power
lead. Conversely, the GeForce 6800
Ultra is a two-slot card that requires a
monstrous 480W power supply and two
power leads from your system’s PSU.
But don’t rush to a conclusion—theGeForce 6800 Ultra has some important
features the Radeon X800 XT lacks,
namely 32-bit floating-point color and
Pixel Shader 3.0 capabilities. If develop-
ers plan to support Pixel Shader 3.0, it
could mean that programmable shader
games that use the spec will look sig-
nificantly better on nVidia hardware
than ATI hardware, which only supports
24-bit floating-point color.
We’ll break all this down—and give
you the inside scoop on image quality
differences between the two cards—in
next month’s Maximum PC. But for
now, know this: Both of these 3D cards
are lightning fast.FORMAT X-SPEED TRANSFER RATE TIMEGAIN FROM
PREVIOUS SPEED
DVD+R 8x 10.57MB/sec 8:28 5:52
DVD+R 4x 5.28MB/sec 14:20 9:12
DVD+R 2.4x 2.65MB/sec 23:32 N/ADVD-R 4x 5.28MB/sec 14:50 14:35
DVD-R 2x 2.65MB/sec 29:25 N/ADVD+RW 4x 5.28MB/sec 13:51 10:09
DVD+RW 2.4x 2.65MB/sec 24:00 N/A
Higher-speed media may be available by the time you read this. We declined to include prototype high-speed media in these
tests. But these figures give you an idea of what to expect.
The naked truth about x-speeds: The yellow line
represents the speed of the disc’s rotation, and
the green line represents the rate at which data is
being written. The PX-708A begins writing at 6x
until about 700MB into the disc. It then ratchets up
to 8x and maintains this rate until 3.3GB into the
disc. Finally, it slows down to 4x to make reading
data at the outer extremities less error-prone.
As a result, the average x-speed of the drive is
actually 6.7x, and that’s only when you’re writing
the full 4.7GB capacity of the disc.How Fast Does 8x DVD
Actually Record?
The test: Used by 8x and faster
DVD burners, Zone-CLV writing
schemes divide the disk into multi-
ple zones and spin the disc slower
in the inner rings and faster in the
outer rings. Because of this speed
variance, we’ve always wondered
exactly how big a speed increase
an 8x burner boasts over a 2x and
a 4x drive. In order to test how
zone-based recording affects disc
writing speed, we used Plextor’s
speedy 708A (fi rmware revision
1.06) for our DVD burner. We used
Ahead’s Nero (version 6.3.1.6)
to adjust the write speed, and
Verbatim media to create 4.5GB
data DVDs.
The results: The chart speaks for
itself—DVD burners experience
diminishing returns in perfor-
mance rates as recordable DVD
drives increase their x-speeds.
While a 4x DVD burner ran
twice as fast as a 2x model, we
discovered that an 8x drive was
not twice as fast as a 4x drive; it
was off by approximately a min-
ute and a half (presumably, 12x
drives will suffer an even greater
penalty).
Nonetheless, we concluded
that higher x-speeds in DVD burn-
ers are more valuable than higher
x-speeds in CD burners. The most
popular application for DVD burn-
ers is creating DVD Video, and the
higher the bitrate (and thus fi le
size) of the video you burn, the
better quality you’ll get. Because
you’ll frequently maximize bitrate
in order to burn the entire capacity
of a 4.7GB recordable DVD, you’ll
benefi t more from the speed gains
at the outer edges.