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Pipelines – different things to different folks

My ears are ringing from all the pipelines that have been piped into them this week. Nvidia has one in their 6150, two in their 6200, and 24 in their 7800, while ATI has six in their 800, and 16 in their 1800 (relying purely on early leaks on the web about Ruby’s new r520). Then in the Southeast we ...

Robert Dow

My
ears are ringing from all the pipelines that have been piped into them
this week. Nvidia has one in their 6150, two in their 6200, and 24 in
their 7800, while ATI has six in their 800, and 16 in their 1800 (relying
purely on early leaks on the web about Ruby’s new r520).

Then in the Southeast we saw the other pipelines go dry as refineries
shut down before they were blown over. It’s been a tough couple of weeks
for the suppliers of pipelines.

In GPUland we’re about to enter into the great debate about what is
and what isn’t a pipeline, or what is a good pipeline or a great pipeline.
It will be a discussion about fragments, and memory I/O, and floating
points vs. vectors. All that noise will be unleashed when ATI officially
announces the r520 and explains why it’s the real deal and Nvidia’s
award winning 7800 is just good enough.

The news coming out of Taiwan via Digitimes, combined with IDC’s upbeat
forecast for the Pacific region, is that Q4 is going to be great for
PCs and GPUs. Well, I couldn’t be happier. That, combined with the huge
announcement of the Xbox 360, is going to leave most of the consumers
of pixels somewhere between stunned and bedridden. And when Microsoft
starts to explain how and why their unified shader is more better’er
than Sony’s conventional function-specific shaders, you won’t know a
pipeline from a pipe cleaner.

And it’s not going to let up, because the next crusade will be HDR
and the right and wrong way to do that. Is HDR done in the shader? Where?
Is that part of the pipeline? When does a shader stop being a ÒshaderÓ
and become a FPP and not a pipeline? If you saw a pipeline would you
recognize it?

I don’t have an answer to these riddles because they are questions
that can’t be answered with technical agreement. And that’s because
they have been created by marketing and not engineers. So marketing
types will create new and exciting names for things that process pixels
and vertexes and do memory management and perform software operations
that polish pixels, and we’ll be expected to remember them, and understand
them. We don’t really have to understand them, we just have to be able
to repeat what ATI and Nvidia say in their white papers, so other people
will think we understand them. And to help us, the words will be either
all capital letters, or a combination of capital letters. As a matter
of fact, I was thinking about writing one of these editorials in all
caps, but Kathleen and Marilyn threatened to hide all my games if I
did.

Nonetheless, we need a way to discuss the parallelism in today’s GPUs
and a way to relate implied performance. But we’re at risk of falling
into the same trap that Intel did with the MHz game—at a certain
point it doesn’t reveal enough about the real performance, even though
more is needed. No doubt we will see GPUs with 256 “pipes”
in them, and it won’t be that far away. But when we cross the 32-pipe
threshold (next year), the scaling of performance will shift to other
factors and they will be more difficult to turn into simple sound bites.

The next stage of graphics performance will be measured in compiler
efficiency. As operating systems like Apple’s System 10 and Microsoft’s
Vista bring more of the GPU to the forefront and simultaneously steal
some of the differentiation away from the GPUs like memory management,
the GPU sup-pliers will have to find other parameters to distinguish
their parts. Even benchmarks won’t be enough now that -Nvidia has been
successful in downgrading the importance of 3Dmark and we now score
dozens of FPS counters in each game (and when will that meaningless
game end?).

And while we’re struggling to distinguish and praise the newest crop
of GPUs, the little supercomputers on a chip that are a marvel to contemplate,
their little brothers the IGPs are growing up and sporting pipelines,
too.

This is terrific fun and what gets me out of bed and onto too many
airplanes every day. It’s exciting and it never stops. But we are at
risk of getting too far ahead of the people with the money—those
consumers. If the games can’t keep up and take advantage of these new
multi-dozen-pipelined GPUs, and the purveyors of them can’t communicate
their value in simple terms, the consumers will turn off. And its damn
hard to lead a parade when you’re the only one in it, no matter how
many pipe organs you’ve got.