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Subject: Xbox 360 hardware vs PS3 hardware. A detailed comparison. Sat Jun 05, 2010 8:08 am
Before I begin, I will tell you all that I'm going to keep this as bias free as possible...but occasionally you will read my opinion on why I think one spec is important. I will also provide multiple sources. *Some info subject to change
You always hear people talking about the Cell and it's "potential". In reality though the GPUs are just as important if not more important. The GPUs are what renders the images you see on screen. And no matter how much of the graphics processing workload you load on a CPU, the majority of the graphics you see (textures, polygon models, draw distances, etc) are being rendered by the GPU.
So which GPU is better? Well let's compare the RSX (PS3's GPU) to the Xenos (X360's GPU). The RSX has 24 pixel shader pipelines and 8 vertex shader pipelines. It’s capable of 136 shader operations per clock and performs 74.8 billion shader operations per second. It's clocked at 550 MHZ. The Xenos is clocked at 500 MHZ but has 48 unified shader units or pipelines. It performs 192 shader operations per clock and 96 billion shader operations per second. Think of the shader pipelines as water faucets, the bigger the faucet the more water that can go through...Same idea applies here. And this is just comparing the bare naked GPUs.
I'm not even factoring in the eDRAM...which is the prime reason more games on the 360 use MSAA (the most effective AA setting.) than on the PS3. It's also a big reason why multiplatform games in general tend to look better on the X360. How could this one factor be so huge? Well let's talk about what the eDRAM does. The eDRAM allows for extermely fast access to framebuffers. It can essentially put off a huge workload when it comes to AA and framebuffers, one reason why the X360 is more efficient with memory as well. Developers could use the eDRAM to turn on 2xMSAA at 720p essentially for free and 4xMSAA (using the memory efficient tile mechanism on the Xenos's main RAM with less performance hit.). This is also a reason why alot of developers prefer to run games at 720p with AA instead of higher resolutions on the X360...since 10 MB of eDRAM isn't exactly enough for 1080p buffers.
This also brings up the topic of RAM (Random Access Memory for the GPU and CPU). The memory on the X360 is one unified 512 MBs of RAM clocked at 700 MHz, with 32 MBs being used for the OS (480 MB RAM total for game engine purposes). The memory on the PS3 is more segregated. The GPU has 256 MB of 700 MHz RAM and the CPU has 256 MB of 3.2 GHz RAM, with 50 MBs being used for the OS (462 MB of RAM for game engine purposes). Yes, half of the PS3's RAM is faster than the X360's main RAM. Though it should be noted that the X360's RAM is alot more flexible. If the developers want to make an MMORPG or something that uses 70% of the main RAM for CPU functions then it would be possible on the X360. On the PS3 architecture, only the GPU can access RAM from the CPU, and not the other way around. It's not particularly a HUGE deal though, as the Cell doesn't use that much RAM in the first place...It was worth noting though. Anyways, how does this apply to GPUs? Well with more memory efficiency the GPUs can essentially save more memory for textures. The Xenos is very smart when it comes to texture storing. It can store twice as much textures on average with the same amount of memory, and that's without any compression. Combine that with the fact that the Xenos doesn't use as much memory in general for framebuffers and AA, and you can store quite a bit of textures on the X360's RAM compared to the PS3. This is where texture streaming with Blu-ray comes to play on the PS3. Developers can purposely store textures on the disc to save RAM. The ratio of storing textures on RAM vs storing textures on Blu-ray (when comparing how much space it occupies on the respective formats), is 1:50 (1:100 on the Xenos technically because of it's memory efficiency). So an uncompressed 10 MB texture would take 1 GB on a Blu-ray disc. You can see where the limitations are here. PS3 games like Uncharted 2 and GOW3 use texture streaming extensively which results in a huge blimp in disc size. Yet games like Alan Wake and Gears 2 which have very good texture quality, don't use anywhere near as much disc space (hell, Alan Wake is only 2.6 GBs of game data not counting the audio and video files!). I should also mention disc read speeds. The DVD drive on the X360 can read 12 MB/S while the Blu-ray Drives on the PS3 can read 9 MB/S. This is essentially why some first generation PS3 titles had to have duplicated data. It's not as bad now a days, thanks to HDD streaming of data, which can also be achieved on the X360...but thanks to the Arcade SKU some developers won't force the HDD features on their games.
Now that's out of the way. Let's talk about the CPUs. The Xenon processor is essentially based on the Cell, but uses a different architecture. The Xenon has 3 separate cores each running at 3.2 GHz. Each core has 2 hardware threads, so 6 total hardware threads. The Cell has 1 central core and 7 SPUs. 1 SPU is not used, and another is used for OS purposes. So 5 SPUs total. The Cell pushes around 8 hardware threads...So technically it's 25% more powerful, I guess you could say...But the Xenon will never really use all of it's hardware threads unless game developers are putting alot of CPU calculations (AI and physics) on their games. The biggest advantage of the Cell is the fact that it can use it's SPUs for some GPU processes, as seen in many PS3 exclusives. The Xenon can perform GPU processes as well (some of Alan Wake's lighting and post processing was actually being done on the CPU side of things), but it can't be used effectively for multiple GPU processes since it's unified. This is where PS3 developers can leverage. Although the RSX is clearly the weak point of the PS3's architecture, alot can be done on the Cell's SPUs. But theoritically the RSX+5 SPU working on Graphics processing+Blu-ray texture streaming > Xenos+edram+small scale help from CPU. Realistically though, some SPUs will have to be used for CPU calculations or else PS3 games could potentially be very linear and scripted. I'd also like to point out a few things that I said earlier.
Because of the RSX's low efficiency with memory, MSAA (probably the best version of AA) isn't used more in PS3 games..BUT developers have found other methods to keep the game anti-aliased, though not as effective. QAA and MLAA are two which could be done on the Cell's SPU. QAA makes the image AAed but could potentially blur the image altogether. Some say MLAA is equivalent to 16xMSAA, which is a little farfetched....Sure on a still image it's equivalent to 16xMSAA but it's hardly effective in motion. GOW3 uses a slightly better version of MLAA, but to those who own GOW3 you can do the comparison yourself. Take a screenshot or just stand still while playing the game and you will see hardly any jaggies, but while moving jaggies become more apparent. This is also all subjective on developer resources, if games are using the Cell processor for other things (lighting, post processing, and such) then they will hardly have resources for the alternate AA implementations I stated earlier. So overall, the eDRAM is a huge bonus considering it isn't as big of a performance hit to turn on MSAA.
So behind this geeky tech stuff, you will hit a dead end if you are trying to truely find which console is better when it comes to sheer power. Both the X360 and the PS3 very powerful architectures with their own strengths and weaknesses. But in the end of the day, it all comes down to the software and game engines, and the developers attitude on art style.
Subject: Xbox 360 hardware vs PS3 hardware. A detailed comparison. Sat Jun 05, 2010 8:08 am
Before I begin, I will tell you all that I'm going to keep this as bias free as possible...but occasionally you will read my opinion on why I think one spec is important. I will also provide multiple sources. *Some info subject to change
You always hear people talking about the Cell and it's "potential". In reality though the GPUs are just as important if not more important. The GPUs are what renders the images you see on screen. And no matter how much of the graphics processing workload you load on a CPU, the majority of the graphics you see (textures, polygon models, draw distances, etc) are being rendered by the GPU.
So which GPU is better? Well let's compare the RSX (PS3's GPU) to the Xenos (X360's GPU). The RSX has 24 pixel shader pipelines and 8 vertex shader pipelines. It’s capable of 136 shader operations per clock and performs 74.8 billion shader operations per second. It's clocked at 550 MHZ. The Xenos is clocked at 500 MHZ but has 48 unified shader units or pipelines. It performs 192 shader operations per clock and 96 billion shader operations per second. Think of the shader pipelines as water faucets, the bigger the faucet the more water that can go through...Same idea applies here. And this is just comparing the bare naked GPUs.
I'm not even factoring in the eDRAM...which is the prime reason more games on the 360 use MSAA (the most effective AA setting.) than on the PS3. It's also a big reason why multiplatform games in general tend to look better on the X360. How could this one factor be so huge? Well let's talk about what the eDRAM does. The eDRAM allows for extermely fast access to framebuffers. It can essentially put off a huge workload when it comes to AA and framebuffers, one reason why the X360 is more efficient with memory as well. Developers could use the eDRAM to turn on 2xMSAA at 720p essentially for free and 4xMSAA (using the memory efficient tile mechanism on the Xenos's main RAM with less performance hit.). This is also a reason why alot of developers prefer to run games at 720p with AA instead of higher resolutions on the X360...since 10 MB of eDRAM isn't exactly enough for 1080p buffers.
This also brings up the topic of RAM (Random Access Memory for the GPU and CPU). The memory on the X360 is one unified 512 MBs of RAM clocked at 700 MHz, with 32 MBs being used for the OS (480 MB RAM total for game engine purposes). The memory on the PS3 is more segregated. The GPU has 256 MB of 700 MHz RAM and the CPU has 256 MB of 3.2 GHz RAM, with 50 MBs being used for the OS (462 MB of RAM for game engine purposes). Yes, half of the PS3's RAM is faster than the X360's main RAM. Though it should be noted that the X360's RAM is alot more flexible. If the developers want to make an MMORPG or something that uses 70% of the main RAM for CPU functions then it would be possible on the X360. On the PS3 architecture, only the GPU can access RAM from the CPU, and not the other way around. It's not particularly a HUGE deal though, as the Cell doesn't use that much RAM in the first place...It was worth noting though. Anyways, how does this apply to GPUs? Well with more memory efficiency the GPUs can essentially save more memory for textures. The Xenos is very smart when it comes to texture storing. It can store twice as much textures on average with the same amount of memory, and that's without any compression. Combine that with the fact that the Xenos doesn't use as much memory in general for framebuffers and AA, and you can store quite a bit of textures on the X360's RAM compared to the PS3. This is where texture streaming with Blu-ray comes to play on the PS3. Developers can purposely store textures on the disc to save RAM. The ratio of storing textures on RAM vs storing textures on Blu-ray (when comparing how much space it occupies on the respective formats), is 1:50 (1:100 on the Xenos technically because of it's memory efficiency). So an uncompressed 10 MB texture would take 1 GB on a Blu-ray disc. You can see where the limitations are here. PS3 games like Uncharted 2 and GOW3 use texture streaming extensively which results in a huge blimp in disc size. Yet games like Alan Wake and Gears 2 which have very good texture quality, don't use anywhere near as much disc space (hell, Alan Wake is only 2.6 GBs of game data not counting the audio and video files!). I should also mention disc read speeds. The DVD drive on the X360 can read 12 MB/S while the Blu-ray Drives on the PS3 can read 9 MB/S. This is essentially why some first generation PS3 titles had to have duplicated data. It's not as bad now a days, thanks to HDD streaming of data, which can also be achieved on the X360...but thanks to the Arcade SKU some developers won't force the HDD features on their games.
Now that's out of the way. Let's talk about the CPUs. The Xenon processor is essentially based on the Cell, but uses a different architecture. The Xenon has 3 separate cores each running at 3.2 GHz. Each core has 2 hardware threads, so 6 total hardware threads. The Cell has 1 central core and 7 SPUs. 1 SPU is not used, and another is used for OS purposes. So 5 SPUs total. The Cell pushes around 8 hardware threads...So technically it's 25% more powerful, I guess you could say...But the Xenon will never really use all of it's hardware threads unless game developers are putting alot of CPU calculations (AI and physics) on their games. The biggest advantage of the Cell is the fact that it can use it's SPUs for some GPU processes, as seen in many PS3 exclusives. The Xenon can perform GPU processes as well (some of Alan Wake's lighting and post processing was actually being done on the CPU side of things), but it can't be used effectively for multiple GPU processes since it's unified. This is where PS3 developers can leverage. Although the RSX is clearly the weak point of the PS3's architecture, alot can be done on the Cell's SPUs. But theoritically the RSX+5 SPU working on Graphics processing+Blu-ray texture streaming > Xenos+edram+small scale help from CPU. Realistically though, some SPUs will have to be used for CPU calculations or else PS3 games could potentially be very linear and scripted. I'd also like to point out a few things that I said earlier.
Because of the RSX's low efficiency with memory, MSAA (probably the best version of AA) isn't used more in PS3 games..BUT developers have found other methods to keep the game anti-aliased, though not as effective. QAA and MLAA are two which could be done on the Cell's SPU. QAA makes the image AAed but could potentially blur the image altogether. Some say MLAA is equivalent to 16xMSAA, which is a little farfetched....Sure on a still image it's equivalent to 16xMSAA but it's hardly effective in motion. GOW3 uses a slightly better version of MLAA, but to those who own GOW3 you can do the comparison yourself. Take a screenshot or just stand still while playing the game and you will see hardly any jaggies, but while moving jaggies become more apparent. This is also all subjective on developer resources, if games are using the Cell processor for other things (lighting, post processing, and such) then they will hardly have resources for the alternate AA implementations I stated earlier. So overall, the eDRAM is a huge bonus considering it isn't as big of a performance hit to turn on MSAA.
So behind this geeky tech stuff, you will hit a dead end if you are trying to truely find which console is better when it comes to sheer power. Both the X360 and the PS3 very powerful architectures with their own strengths and weaknesses. But in the end of the day, it all comes down to the software and game engines, and the developers attitude on art style.
