http://www.extremetech.com/article2/0,1558,1820428,00.asp
Highlights:
Right now, the raging message board wars about next-gen consoles seem centered on which is more powerful. Is having the most powerful console a recipe for certain success? I don't think so. Is coming out first enough to do it? Not if the Dreamcast has taught us anything.
There's an update on the blog of Xbox Live's own Major Nelson, with a Microsoft-prepared counter-argument that "proves" the Xbox 360 is in fact more powerful than the PS3. It's an interesting read, even if many of the arguments are flawed. It brings up a good point: Either system can be made to look more powerful than the other, depending on how you want to bend the specs.
In truth, the systems aren't entirely comparable. The 360 has a single, unified 512MB bank of GDDR3 memory. The PS3 has 256MB of GDDR3 connected to the graphics chip and a bank of 256MB XDR connected to the CPU. That's more total bandwidth in the PS3's favor, but what if there's some penalty for the graphics chip accessing the XDR? Then there's the issue of the Xbox 360's "smart EDRAM,"--10MB of embedded RAM that stores the back buffer, z-buffer, and stencil buffer. It performs a bunch of useful blending and z-compare functions right within the RAM so that the graphics chip doesn't have to. It's also got an insane 256 GB/sec of bandwidth to the GPU. The PS3's graphics chip is a traditional PC architecture, with separate and discrete vertex and pixel pipelines. The 360 uses a new unified shader architecture with 48 ALUs, each capable of performing multiple shader operations per cycle and fed by a scheduler intended to keep them fully utilized all the time. So when it comes to graphics, it's simply not possible to tell, simply by looking at the numbers, which one is more "powerful."
The CPUs are a similar story. The 360 uses a three-core PowerPC derivative with a shared L2 cache, where each core can process two simultaneous threads. It's got SIMD floating-point units similar to SSE3, and is certainly no number-crunching slouch. The PS3 uses the Cell, which has a single PowerPC core and eight "synergistic processing units" optimized for particular tasks. What these SPUs are good at and what they're not is a point of contention, even among programmers working on it, because it's no small task to get the Cell CPU firing on all cylinders, if you will. Is it more powerful than the 360's CPU? Well, it certainly has a higher peak "gigaflops" rating, but that doesn't really mean it's going to be better for games. Games use operations like load/store, and perform logic functions that need to access memory in a random, rather than streaming, fashion. That's not necessarily the Cell chip's forte. As with the GPUs, the raw numbers don't tell the whole story here. It's simply not possible to look at the specs and say "this one is more powerful for what game developers need to do."
Right now, there are no developers working on kits that include hardware resembling the true final production Xbox 360 or Playstation 3 systems. It's not until they start banging on that final silicon that we'll really know which is more powerful, and I suspect there will still be disagreement. At the end of the day, in a general sense, I think both systems are going to be able to get about the same quality stuff on the screen.
Highlights:
Right now, the raging message board wars about next-gen consoles seem centered on which is more powerful. Is having the most powerful console a recipe for certain success? I don't think so. Is coming out first enough to do it? Not if the Dreamcast has taught us anything.
There's an update on the blog of Xbox Live's own Major Nelson, with a Microsoft-prepared counter-argument that "proves" the Xbox 360 is in fact more powerful than the PS3. It's an interesting read, even if many of the arguments are flawed. It brings up a good point: Either system can be made to look more powerful than the other, depending on how you want to bend the specs.
In truth, the systems aren't entirely comparable. The 360 has a single, unified 512MB bank of GDDR3 memory. The PS3 has 256MB of GDDR3 connected to the graphics chip and a bank of 256MB XDR connected to the CPU. That's more total bandwidth in the PS3's favor, but what if there's some penalty for the graphics chip accessing the XDR? Then there's the issue of the Xbox 360's "smart EDRAM,"--10MB of embedded RAM that stores the back buffer, z-buffer, and stencil buffer. It performs a bunch of useful blending and z-compare functions right within the RAM so that the graphics chip doesn't have to. It's also got an insane 256 GB/sec of bandwidth to the GPU. The PS3's graphics chip is a traditional PC architecture, with separate and discrete vertex and pixel pipelines. The 360 uses a new unified shader architecture with 48 ALUs, each capable of performing multiple shader operations per cycle and fed by a scheduler intended to keep them fully utilized all the time. So when it comes to graphics, it's simply not possible to tell, simply by looking at the numbers, which one is more "powerful."
The CPUs are a similar story. The 360 uses a three-core PowerPC derivative with a shared L2 cache, where each core can process two simultaneous threads. It's got SIMD floating-point units similar to SSE3, and is certainly no number-crunching slouch. The PS3 uses the Cell, which has a single PowerPC core and eight "synergistic processing units" optimized for particular tasks. What these SPUs are good at and what they're not is a point of contention, even among programmers working on it, because it's no small task to get the Cell CPU firing on all cylinders, if you will. Is it more powerful than the 360's CPU? Well, it certainly has a higher peak "gigaflops" rating, but that doesn't really mean it's going to be better for games. Games use operations like load/store, and perform logic functions that need to access memory in a random, rather than streaming, fashion. That's not necessarily the Cell chip's forte. As with the GPUs, the raw numbers don't tell the whole story here. It's simply not possible to look at the specs and say "this one is more powerful for what game developers need to do."
Right now, there are no developers working on kits that include hardware resembling the true final production Xbox 360 or Playstation 3 systems. It's not until they start banging on that final silicon that we'll really know which is more powerful, and I suspect there will still be disagreement. At the end of the day, in a general sense, I think both systems are going to be able to get about the same quality stuff on the screen.
FUD 1, Reason 0
