All of Bogie's post was copy and pastes from the most well known XBox vs PS3 comparison on the net, you will all have seen the graphs from it. The original poster is unknown, but this was one of the Xbox 360 biased comparisons i was describing. Here is a link:
http://rofl-at.us/?page_id=85
It was created before the PS3 was released, and is based on incomplete information from a Sony conference (possibly at E3).
This is a more reliable comparison:
http://www.winsupersite.com/showcase/xbox360_ps3_wii.asp
However, a lot of this info is basic.
Unfortunately, he has no idea how the Xbox 360 truly works. Had he known, he would probably not look so foolish. Considering Microsoft has given us the full details of their box, as you can see below, the PS3 isn't as good as we aer led to believe.
You do not know the inner workings of the console either, you copy and pasted a comparison from another site, none of it is your own. I spent well over an hour writing my comparison, researching everything, taking my info from many sources and learning about how each bit works so i could write my own analysis.
The Xbox 360 has many more advantages than he listed, but since we all know his agenda, it should come as no surprise.
The Xbox 360 has 278.4 GB/s of memory system bandwidth while the PS3 has less than one-fifth of Xbox 360's (48 GB/s) of total memory system bandwidth. Think about that now for a second. The memory system bandwidth in Xbox 360 exceeds the PS3's by five times. That is huge. Also, when looking at general purpose computing, the Xbox 360 CPU has 3 times the general purpose processing power of the Cell. Not to mention, the Xbox 360 GPU design is more flexible and it has more processing power than the PS3 GPU.
The graphics memory system bandwidth is the same for both on the GDDR3 RAM (around 22.4GB/s). The memory system bandwidth of the XDR RAM is 25.6GB/s. The bandwidth for the eDRAM is so large because it is internal, and it only has a minute 10MB of memory, it is just a big cache for the GPU... Its main process is anti-aliasing, would that would not be required if the main GPU processes were up to scratch.
The Xbox 360 processor was designed to give game developers the power that they actually need, in an easy to use form. The Cell processor has impressive streaming floating-point power that is of limited use for games.
Because the Xbox 360 and its processor setup is closer to a PC in design. The PS3 processor is relatively unique and before the PS3 has never been used for gaming. 'easy to program' just means the methods have been around for years. The PS3 requires a different approach to programming, but yields better results if you make use of its hardware properly.
The majority of game code is a mixture of integer, floating-point, and vector math, with lots of branches and random memory accesses. This code is best handled by a general purpose CPU with a cache, branch predictor, and vector unit.
The Cell's seven DSPs (what Sony calls SPEs) have no cache, no direct access to memory, no branch predictor, and a different instruction set from the PS3's main CPU. They are not designed for or efficient at general purpose computing. DSPs are not appropriate for game programming.
Xbox 360 has three general purpose CPU cores. The Cell processor has only one.
Indeed, the Xbox 360 has 3 PPE cores, whilst the Cell Processor has one main PPE core and 7 SPE cores (one of them used primarily for the operating system, 6 for gaming). You are wrong, the SPE cores each have their own 256KB cache. You were right when you said the 7 SPE cores do not have direct access to the memory. But the PPE core (the central core) does have access to the RAM, aswell as having its own 512MB cache. The PPE core sort of 'outsources' its processes to the SPE cores (i'm not sure what the computing term is for outsourcing).
What you neglect to mention is that the Xbox 360 CPU and the GPU both use the 512MB RAM . The PS3 has seperate VRAM and main RAM. the XDR (main) RAM can be accessed by the CPU main core directly, at a higher memory bandwidth.
Xbox 360's CPUs has vector processing power on each CPU core. Each Xbox 360 core has 128 vector registers per hardware thread, with a dot product instruction, and a shared 1-MB L2 cache. The Cell processor's vector processing power is mostly on the seven DSPs.
Dot products are critical to games because they are used in 3D math to calculate vector lengths, projections, transformations, and more. The Xbox 360 CPU has a dot product instruction, where other CPUs such as Cell must emulate dot product using multiple instructions.
All of which leads to the fact the PS3 generates over double the Dot product calculations per second
That point is irrelevant and leads to nothing.
Cell's streaming floating-point work is done on its seven DSP processors. Since geometry processing is moved to the GPU, the need for streaming floating-point work and other DSP style programming in games has dropped dramatically.
You have already mentioned this, it just reinforces the fact that the Xbox 360 processor is closer to that of a PC processor with gaming in mind. It does not in any way mean it is better for gaming as the PS3 processor has shown.
Just like with the PS2's Emotion Engine, with its missing L2 cache, the Cell is designed for a type of game programming that accounts for a minor percentage of processing time.
The cell has an L2 cache, 512MB for the main PPE processor and a further 256KB for each of its cores, so that statement is simply wrong.
Sony's CPU is ideal for an environment where 12.5% of the work is general-purpose computing and 87.5% of the work is DSP calculations. That sort of mix makes sense for video playback or networked waveform analysis, but not for games. In fact, when analyzing real games one finds almost the opposite distribution of general purpose computing and DSP calculation requirements. A relatively small percentage of instructions are actually floating point. Of those instructions which are floating-point, very few involve processing continuous streams of numbers. Instead they are used in tasks like AI and path-finding, which require random access to memory and frequent branches, which the DSPs are ill-suited to.
Again, this is irrelevant, 'general purpose computing' in this sense means PPE. That paragraph can be simplified to: "The PS3 has 1 PPE core and 7 SPE cores." The 12.5% refers to the percentage of 1/8 of the processing power... And the last bit of the paragraph again is assuming SPEs are not good for gaming. The PPE uses the SPE and converts them into the relevant calculations for games. You are assuming that the use of SPE cores automatically makes the processor worse. This is the whole basis behind the viewpoint that they can not be compared, the PS3 utilises the advantages of the SPE by using a PPE to convert the calculations into the relevant form for gaming.
Based on measurements of running next generation games, only ~10-30% of the instructions executed are floating point. The remainders of the instructions are load, store, integer, branch, etc. Even fewer of the instructions executed are streaming floating point?"probably ~5-10%. Cell is optimized for streaming floating-point, with 87.5% of its cores good for streaming floating-point and nothing else.
Referring to my previous point, the PPE uses the SPEs for its calculations.
Even ignoring the bandwidth limitations the PS3's GPU is not as powerful as the Xbox 360's GPU.
There are no bandwidth limitations. The bandwidth between the graphics chip and the DDR3 RAM used in both is the same. Unless you mean the 10MB on internal eDRAM which has limited use.
Below are the specs from Sony's press release regarding the PS3's GPU.
RSX GPU
550 MHz
Independent vertex/pixel shaders
51 billion dot products per second (total system performance)
300M transistors
136 shader operations per clock
The interesting ALU performance numbers are 51 billion dot products per second (total system performance), 300M transistors, and more than twice as powerful as the 6800 Ultra.
The 51 billions dot products per cycle were listed on a summary slide of total graphics system performance and are assumed to include the Cell processor. Sony's calculations seem to assume that the Cell can do a dot product per cycle per DSP, despite not having a dot product instruction.
The PPE utilises the SPEs to create a dot product calculation per cycle...
However, using Sony's claim, 7 dot products per cycle * 3.2 GHz = 22.4 billion dot products per second for the CPU. That leaves 51 ?" 22.4 = 28.6 billion dot products per second that are left over for the GPU. That leaves 28.6 billion dot products per second / 550 MHz = 52 GPU ALU ops per clock.
It is important to note that if the RSX ALUs are similar to the GeForce 6800 ALUs then they work on vector4s, while the Xbox 360 GPU ALUs work on vector5s. The total programmable GPU floating point performance for the PS3 would be 52 ALU ops * 4 floats per op *2 (madd) * 550 MHz = 228.8 GFLOPS which is less than the Xbox 360's 48 ALU ops * 5 floats per op * 2 (madd) * 500 MHz= 240 GFLOPS.
Regardless, the PS3 still produces more product dot calculations per second...
With the number of transistors being slightly larger on the Xbox 360 GPU (330M) it's not surprising that the total programmable GFLOPs number is very close.
That includes the eDRAM. The eDRAM has ~105million transistors which are not used for the majority of calculations. They are used for anti-aliasing and other demanding tasks that don't actually take up much memory. That eDRAM is actually very good, but the main GPU is lacking in certain areas compared to the RSX.
The PS3 does have the additional 7 DSPs on the Cell to add more floating point ops for graphics rendering, but the Xbox 360's three general purpose cores with custom D3D and dot product instructions are more customized for true graphics related calculations.
Like i said, the main PPE core translates the SPE calculations for graphics related calculations.
The 6800 Ultra has 16 pixel pipes, 6 vertex pipes, and runs at 400 MHz. Given the RSX's 2x better than a 6800 Ultra number and the higher frequency of the RSX, one can roughly estimate that it will have 24 pixel shading pipes and 4 vertex shading pipes (fewer vertex shading pipes since the Cell DSPs will do some vertex shading). If the PS3 GPU keeps the 6800 pixel shader pipe co-issue architecture which is hinted at in Sony's press release, this again gives it 24 pixel pipes* 2 issued per pipe + 4 vertex pipes = 52 dot products per clock in the GPU.
If the RSX followed the 6800 Ultra route, it will have 24 texture samplers, but when in use they take up an ALU slot, making the PS3 GPU in practice even less impressive. Even if it does manage to decouple texture fetching from ALU co-issue, it won't have enough bandwidth to fetch the textures anyways.
This is the evidence that the article is outdated. You can see the relevant info on this in my comparison post.
For shader operations per clock, Sony is most likely counting each pixel pipe as four ALU operations (co-issued vector+scalar) and a texture operation per pixel pipe and 4 scalar operations for each vector pipe, for a total of 24 * (4 + 1) + (4*4) = 136 operations per cycle or 136 * 550 = 74.8 GOps per second.
Given the Xbox 360 GPU's multithreading and balanced design, you really can't compare the two systems in terms of shading operations per clock. However, the Xbox 360's GPU can do 48 ALU operations (each can do a vector4 and scalar op per clock), 16 texture fetches, 32 control flow operations, and 16 programmable vertex fetch operations with tessellation per clock for a total of 48*2 + 16 + 32 + 16 = 160 operations per cycle or 160 * 500 = 80 GOps per second.
All of that was mentioned in my post, but with the relevant up to date info, not info from a press conference from 2005.
Overall, the automatic shader load balancing, memory export features, programmable vertex fetching, programmable triangle tesselator, full rate texture fetching in the vertex shader, and other well beyond shader model 3.0 features of the Xbox 360 GPU should also contribute to overall rendering performance.
What in the what now? You just described the basic functions of a graphics chip, which is of no consequence in this argument.
Also you didn't reference your source. All my info i wrote myself, and i cross-referenced it with several websites (Using Wikipedia as a starting point as the info for both is all in one place). You just copy and pasted which is actually against the forum rules because you didn't state the relevant source.
EDIT: Dravonic has already pointed out most of these things, fairs dos to him
