I
t didn’t take long after Microsoft demon-
strated DirectX 10.1 at the graphics show
SIGGRAPH for the grousing to begin.
“The new 10.1 update to DX10 makes
the current videocard crop obsolete....
I’m sure that it’s backward compatible
with DX10, but why on earth would MS
do that?” complained one person in the
Internet peanut gallery. And that grouser
wasn’t alone. Far and wide, the complaint
machine cranked away, with most of the
panic coming from those who had plunked
down cash for pricey DX10 cards. Would
those cards now be obsolete?
Absolutely not, Sam Glassenberg, lead
programmer for DX10.1, told Maximum PC.
“The updated API provides full sup-
port for all existing Direct3D 10 hardware
and upcoming hardware that supports the
extended feature set,” Glassenberg said.
“The API is a strict superset. No hardware
support has been removed in DirectX 10.1.”
The update itself, as its name implies, is
mostly incremental. Besides supporting all
of the features of DX10, DX10.1 now makes
several formerly optional features mandatory,
including 4x AA and 32-bit fl oating-point
fi ltering. Microsoft’s rationale for this was
driven by its experience with DX9. Because
many hardware features were not manda-
tory with that spec, graphics vendors cher-
ry-picked which elements to support. This
was particularly troublesome for developers
who had to write multiple render paths that
targeted specifi c videocards.Other new features in DX10.1 seem
aimed at increasing performance. The spec
supports blendable SNORM formats, which
will reduce the number of rendering passes
a graphics card must make when layering
effects in a scene. The updated API also
supports indexable cubemaps, which will
negate the need for CPU intervention (and
should increase performance) when switch-
ing from one cubemap to another.
Still, why didn’t the features get rolled
into the original DX10 cards instead of
dribbling out a few months later after Vista
launched? Nvidia’s Ken Brown explained
that the DX10.1 spec wasn’t available
when GeForce 8800 development started
more than four years ago. “API owners are
always adding new features, but hardwarehas to be fi nalized to meet production
schedules,” Brown told Maximum PC. He
was also quick to calm those folks who
fear instant obsolescence. “Regardless,
DX 10.1 is a minor update that provides
support for only a few new features. DX
10.1 fully supports DX10 hardware; it’s
basically an update to DX10 that extends
the hardware functionality slightly.”
Graphics industry analyst Jon Peddie
agrees that the fear by users is unrealistic,
as DX10.1 will be compatible with DX10.
He also said the people who rushed out
to buy $600 graphics cards aren’t exactly
the kind of folks who use the same GPU
for three years. Peddie said the update is
mostly good because it helps make the
platform more uniform.Is Your DX10 Card Already
Obsolete?
It’s been barely a year since
DirectX 10 debuted, and
even less time since it’s
been supported through
Vista, but Microsoft has
already released a revision
of the spec
Development of the GeForce 8800 series began too late for inclusion of DX10.1 features.The DX10.
update will
not impact
your ability to
play Crysis on
today’s cards.NOVEMBER 2007 MAXIMUMPC 09
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