Something else I noticed about that particular research paper is that the "monochromatic-ness" of the shader makes a huge difference. Most pixel shader operations are done in 3 colors, possibly plus an alpha component. The pixel shading pipelines in a GPU like the RSX have 4-component vector math units to handle these operations. The SPUs in the Cell have similar 4-component vector math units. Ordinarily, one SPU would be able to process one pixel at a time when using full color (or, at best, process 4 pixels at a time, but only one color at a time, requiring 3 or 4 passes for the same net effect). In the research paper, 5 SPUs were able to process 20 pixels at a time (vs. 24 on the 7800 GTX) because their shader was only in one color. For most pixel shader operations, this would not be the case.

In the Killzone presentation, it seems like they've come up with a way to avoid multiple rendering passes, but it still seems to me that the GPU would handle these computations better. But with the vaugeness of the presentation, it's kind of difficult to discuss specifics.

The Insomniac Games paper isn't talking about pixel shaders at all.  "SPU Shaders" are an approach to how the game code is designed with respect to using the SPUs to handle tasks.  It has nothing to do with this discussion.

@ Entroper

About the Insomniac article:

"Most recently, Insomniac has published the ideas behind internal work being done to field 'SPU shader' support across a number of their larger systems.


Designed to alleviate the contextual burden that might affect certain programmers in their approach to Cell, the idea behind SPU shading is to create pipelines within larger SPE-based systems that resemble in spirit the models more generally associated with GPUs. Within this framework, a programmer is able to insert one or more 'shaders' - essentially a fragment of SPU code - that will accomplish custom work inside of the larger system, with code and required data explicitly associated with one another. Shaders are system-specific in nature, and must conform to parameter, code size, and scratch memory norms. From a performance perspective, one of the primary advantages of this model is that independent programming objectives within a system can be addressed while at the same time reducing the need for callbacks and synchronization requirements between the SPE and PPE.

In their provided overview, Insomniac reveals that the igPhysics system developed by Christensen has been the first to be re-worked to support SPU shading. igPhysics was modified to support the dynamic loading of code and transformed into a multistage pipeline, with each stage loading the next. Although the system pipeline itself remains fixed at runtime, the code being run can be dynamic due to the shader model; the resultant system is both faster and simpler than before. The move to the shader model has led Insomniac to the creation of a real system of deferred physics, with performance of roughly twice its immediate predecessor.

Mike Acton indicates that Insomniac will be expanding the number of SPE systems utilizing the shading model going forward, extending next to "...game (AI) logic. Custom shaders for specific types of characters, updating asynchronously on the SPUs."

IMO the article fits well into better understanding the SPEs.

I think you're asking me to misinterpret the underlined sentence. The key words there are "in spirit" and "models", not "GPUs". It's obvious that you're selecting quotes from these articles that happen to sound good, because when you read the whole thing, it really doesn't say anything to refute my statement.

Listen, I'm done with this conversation; I'm not going to have it drag on for 250 posts like your 360 vs. PS3 thread. GPUs are much better suited to running pixel shaders than SPUs; the RSX, not the Cell, is the bottleneck in terms of trying to run a game at 1080p vs 720p. If you still want to disagree, feel free, but I'm not going to dispute it further. I don't really have time to sift through every article you throw my way to show you why it doesn't mean what you want me to think it means.