A placa da 360 ganha em tudo sei lá quantas vezes. vezes mais rápida só na EDRAM e ainda tem a sua memória a funcionar à mesma velocidade da placa da PS3. 6 vezes mais rapida nos vertex shaders. 2 vezes mais poligonos. Mais operações de shaders por segundo não é duas vezes porque tb n tem o dobro de shaders. Tem bastante mais mas n o dobro. Ou seja não se compara uma placa que é baziada no R600 com uma porcaria de uma 7800GTX talvez um pouco melhor pelas caracteristicas é um pouco talvez melhor. A placa da 360 tem shaders unificados. Não tem comparação.
Olhem para quem quiser estar imformado fiz isto. Explico tim tim por tim tim o porquê da placa da 360 é melhor.
Agora vem a parte má da PS3 e o que faz a 360 ser melhor graficamente que a PS3. Vamos para a placa gráfica.
A placa da PS3 é baseada numa ultrapassada 7800GTX porque a PS3 já está pronta à muito mas não era lançada porque não havia produção de blue ray e a placa da 360 é baseada e já usa arquitectura do futuro R600 da ATI ou seja as futuras placas DX10 que serão potentíssimas para ai 4 ou mais vezes mais potentes que uma 7900GTX. Mas as coisas n ficam por aqui agora vou explicar as diferenças técnicas. A placa da 360 processa 500 milhões de triângulos/s e a da PS3 apenas metade 270 milhões/s o que é uma diferença enorme na qualidade dos gráficos. Em 2005 pensava-se que a placa da 360 ia ter 48 billion shader operations per second e a PS3 74.8 billion shader operations per second mas na realidade a 360 faz 96 billion shader ops per second. Como vez a Microsoft não é mentirosa nas especificações até as reduziu. Tb n disse que a placa da 360 tem alguns recursos DX10 só disse depois dela sair, assim está-nos a surpreender cada vez mais ao contrário da sony que só desilude. A placa da 360 tem uma memória designada por EDRAM que processa 256GB/s que está encarregue processa o HDR. o AA (antialiasing são o filtros que tiram o semelhado e faz com que n se note os pixeis e fiquem linhas perfeitas contornos perfeitos e não com serrilhado) as texturas em alta definição o que faz por exemplo com que a 720p a placa da PS3 gaste 28MB e a da 360 apenas 16. E a 360 ainda tem a sua memória a processar que funciona à mesma velocidade da memória da PS3 ou seja 700MHz DDR3 o que dá 1.4GBz. Mas só a EDRAM da 360 que processa 256MB/s é mais rápida 5 vezes que a memória da PS3 e a 360 ainda tem a sua memória a processar. O que torna a placa da 360 melhor que qualquer placa para PC exceptuando as novas 8800GTX dessas ainda n sei qual é melhor. Ainda saíram à pouco tempo e o R600 da ATI só sai em Janeiro para dar cabe do G80 da Nvidea. Ainda nenhuma placa PC usa a EDRAM só as futuras placas da ATI com o R600 e essa memória é muito cara.
A placa da PS3 como tem muito menos poder pode n aguentar resoluções como o 1080p ou pelo menos em jogos mais pesados pois n tem a EDRAM a processar as texturas. Com essa EDRAM a placa da 360 fica livre e com pouca carga o que faz com que faça grandes gráficos sem se esforçar muito pois o HDR o AA que são os filtros muito pesados por sinal e o processamento das texturas principalmente em alta definição são da responsabilidade da EDRAM e não sobrecarrega a placa. Para já não falar que a placa da 360 tem alguns recursos DX10 e a da PS3 não o que pode fazer com que a PS3 nunca tenha os gráficos da 360 mas não os vai ter porque n tem placa para competir com a da 360 a da 360 é sei lá quantas vezes melhor.
A placa da 360 tem 48 shaders unificados e as novas placas DX10 tb usam shader unificados e a PS3 tem 24 pixel shader pipelines e 8 vertex shader pipelines e não são unificados ou seja a 360 pode usar 24 para vertex e outros 24 para pixel shaders ou seja pode manejar como quiser e a placa da PS3 está restringida assim se precisar de mais vertex shaders não tem. E se somares a placa da 360 tem 48 e a da PS3 32 mas só na 360 podes somar porque é unificado. As operações de vertex shader da 360 são literalmente 6 vezes mais rápidas que as da placa da PS3. Se reparares a placa da PS3 leva uma grande cossa da placa da 360. Eu não sei o que tu entendes de hardware mas para o caso de seres como aqueles que n percebem nada podes pensar que ambas têm 256MB. Pois isso não interessa nada a memória é o menos importante nas placas. Pois uma 6600GT de 128 MB é melhor que uma 6600 de 512 MB porque é mais rápida tem mais bits etc. Ambas as placas da 360 e PS3 funcionam a 256 bits. Os bits mais a velocidade das memórias dizem quantos GB a placa processa por segundo. Por exemplo uma placa com 128 bits e que funcione apenas a 400MHz processa 400*128 e divides o resultado por 8 o que dá 6600MB ou seja 6.4 GB. A memória n entra nessas contas e a placa da 360 tem essa EDRAM que só ela é 5 vezes mais rápida que a memória da placa da PS3 o que permite a placa da 360 gastar muito menos memória como já expliquei e ficar muito mais livre. Assim quando a placa da PS3 precisar de mais memória e n tiver a placa da 360 continua a melhorar os gráficos pois ainda tem muita memória disponível e n é sobrecarregada com tudo.
Quanto à RAM a da 360 são 512 MB para RAM e para placa o que faz com que a 360 possa usar 256 para a placa e 256 para RAM ou como as consolas n precisam de muita RAM 400MB para a consola e 112 para a RAM o que faz com que a placa da 360 fique ainda com mais memória do que a da PS3. E a RAM da PS3 são 256MB que funcionam a 3.2 GHz mas a 128 bits. Ou seja a RAM da 360 e a placa funciona à mesma velocidade dos 256 MB da placa da PS3 e a 256 bits. Como a RAM da PS3 é duas vezes mais rápida mas funciona com metade dos bits tem basicamente a mesma taxa de transferência. Ou seja a memória da 360 é 1.4GHz*256bits/8 o que dá 44.8GB/s mais claro os 256GB/s da EDRAM no caso de estarmos a falar da memória da placa e a da PS3 é 256MB para a placa que funcionam à mesma velocidade da memória da 360 ou seja processa 44.8 GB/s e a RAM da PS3 que funciona a 3.2 processa 3.2*128bits/8 o que dá 51.2 o que é uma diferença mínima visto que tem metade dos bits e um pouco mais do que duas vezes a velocidade da memória da 360. E a diferença entre a placa da 360 que tem a sua memória a 44.8GB/s mais 10MBs de EDRAM a 256GB/s em comparação com a da PS3 que só tem os 44.8GB/s é gigantesca. Mesmo as placas do G80 têm uma taxa de transferência de 80GB/s ou seja nada iguala esta memória EDRAM e n te esqueças do que está para trás os shaders os triângulos tudo a placa da 360 é melhor em tudo e sei lá quantas vezes em tudo.
Tb n sei se sabes mas os shaders a velocidade da memória os polígonos as operações de shader os bits é que fazem uma placa ser melhor do que outra e não a quantidade de memória. Por exemplo uma 5200 de 256MB 128 bis é para ai 5 ou 6 vezes mais fraca que uma 6600GT de 128MB e tb de 128 bits porque a 6600GT tem muitos mais shaders e é muito mais rápida funciona a 1GHz e a 5200 a 400MHz ou seja 0.4GHz e tem muito menos shaders e essas coisas. E a diferença só da EDRAM sem polígonos nem shaders nem nada da 360 para a PS3 é de 256GB/s para 44.8GB/s é uma diferença enorme e a placa da 360 ainda tem mais os seus 44.8GB/s igual à PS3 só que tem mais a EDRAM. Mas é claro que depois a memória interessa por exemplo quando a PS3 precisar de mais memória porque esta já n tem mais e a 360 ainda tem porque n sobrecarrega a placa e é como eu expliquei lá em cima a 720p de resolução que equivale a 1200/1024 no PC a placa da 360 precisa de gastar 16MB para processar as texturas de um jogo e a placa da PS3 precisa de 28MB. E a 360 ainda pode ir buscar mais memória pois tem 512MB partilhados entre a RAM e a placa.
E o que faz duas placas com a mesma memória e os mesmos bits serem 5 ou 10 vezes melhor do que outra é os shaders os polígonos a taxa de transferência das memórias. Existe casos de placas com diferenças de poder brutal e têm a mesma memória e os mesmos bits até te dei um exemplo a cima de uma placa com metade da memória da outra e é 5 ou 6 vezes melhor do que a outra e têm os mesmos bits também.
Conclusão a PS3 tem melhor processador mas a 360 têm muito mais placa muito melhor mesmo sei lá quantas vezes. E a placa é muito mais importante que o processador. Com um processador com 4 anos jogamos jogos recentes e com uma placa dessa altura não jogamos. E por exemplo um 3800+ que nem é dual core uma 8800GTX corre os jogos todos no máximo a resoluções incríveis de 1900 porque o mais importante é a placa é ela que faz os gráficos. Olha que de hardware percebo eu.
Olha um texto a dizer o que eu disse em relação á placa resumidamente mas mais detalhado ainda quer dizer eu aprofundei umas coisas a mais do que eles mas eles aprofundaram outras que eu n aprofundei. Eles n falaram daquelas contas das taxas de transferência mas eu como sei e é importante falei.
RSX (PS3GPU) & Xenos (360GPU)
Alright let’s get underway the GPU inside the PS3 is NV47 based which is another name for the 7800GTX. It has 24 pixel shader pipelines and 8 vertex shader pipelines. It’s capable of 136 shader operations per clock and according to Sony it has 256MB of GDDR3 memory at 700MHZ and performs 74.8 billion shader operations per second. Sony also said it’s capable of 1.8 teraflops, which I can tell everyone right now with 100% confidence isn’t true (numbers game) I’m not entirely sure of all the little tricks they used to arrive at such an extreme flops number, but rest assured it isn’t a type of a performance this GPU will ever really achieve. PC videocards such as the X1900XTX have far more raw horsepower than either of the 2 videocards in either console and is pushing a GPU clock speed of up to 650MHZ (some have shipped at 675MHZ) along with 24 more pixel shader pipelines and yet the X1900XTX is just over 500GFLOPS so to even begin entertaining the thought that a less advanced GPU with significantly less raw power could brute force 1.3 teraflops better performance is wishful thinking, but there is no cause to be angry at Sony in this case as they are entitled to market their product regardless of how they choose to do it. As long as they avoid disturbingly untrue statements about the competition its all fair game as far as I’m concerned)
I’m sure some people are wondering how Sony came to the conclusion that the RSX does 136 shader operations per clock or even 74.8 billion shader ops per second? Easy
# The RSX has 24 pixel pipes (each of which performs 5.7 ops) 5.7ops *24 Pixel Pipelines=136.8 shader ops per clock.
# The RSX is clocked at 550MHZ *136 shader ops per clock =74800 (or 74,800,000,000)
There is talk and even an event which took place in Japan in which Sony attended claiming that the RSX will no longer be 550MHZ and it will instead be clocked at 500MHZ and the 256MB of GDDR3 will now be @650MHZ instead of 700. Now there is a lot pointing to this being true, but Sony still hasn’t officially come out and admitted so I’m not sure what to think, but this is a perfect opportunity to see if we learned how to calculate this stuff.
If the RSX is clocked at 500MHZ*136 shader ops per clock that would make the new shader operations per second for the RSX 68 billion instead of the original 74.8 billion weakening the GPU’s performance, but I guess we wont truly find out till the PS3 releases because if anyone has noticed Sony has never posted the RSX clockspeed on the official ps3 site nor did they re-iterate the RSX clockspeed at E3 06. The RSX has 20.8GB/s of video memory bandwidth from the GDDR3 ram. The RSX has an extra 32 GB/sec writing to the system's main memory. If the RSX can fully utilize the memory system it can achieve pushing out 58.2GB/s worth of pixel rendering to memory. The RSX is pretty much a 7800GTX class GPU in some cases its worse in some cases better, nothing that is really new. Now the same can’t be said about the 360’s GPU at all.
Now the 360’s GPU is one impressive piece of work and I’ll say from the get go it’s much more advanced than the PS3’s GPU so I’m not sure where to begin, but I’ll start with what Microsoft said about it. Microsoft said Xenos was clocked at 500MHZ and that it had 48-way parallel floating-point dynamically-scheduled shader pipelines (48 unified shader units or pipelines) along with a polygon performance of 500 Million triangles a second.
Before going any further I’ll clarify this 500 Million Triangles a second claim. Can the 360’s GPU actually achieve this? Yes it can, BUT there would be no pixels or color at all. It’s the triangle setup rate for the GPU and it isn’t surprising it has such a higher triangle setup rate due to it having 48 shaders units capable of performing vertex operations whereas all other released GPUs can only dedicate 8 shader units to vertex operations. The PS3 GPU’s triangle setup rate at 550MHZ is 275 million a second and if its 500MHZ will have 250 million a second. This is just the setup rate do NOT expect to see games with such an excessive number of polygons because it wont happen.
Microsoft also says it can also achieve a pixel-fillrate of 16Gigasamples per second. This GPU here inside the Xbox 360 is literally an early ATI R600, which when released by ATI for the pc will be a Directx 10 GPU. Xenos in a lot of areas manages to meet many of the requirements that would qualify it as a Directx 10 GPU, but falls short of the requirements in others. What I found interesting was Microsoft said the 360’s GPU could perform 48 billion shader operations per second back in 2005. However Bob Feldstein, VP of engineering for ATI, made it very clear that the 360’s GPU can perform 2 of those shaders per cycle so the 360’s GPU is actually capable of 96 billion shader operations per second.
To quote ATI on the 360’s GPU they say.
"On chip, the shaders are organized in three SIMD engines with 16 processors per unit, for a total of 48 shaders. Each of these shaders is comprised of four ALUs that can execute a single operation per cycle, so that each shader unit can execute four floating-point ops per cycle."
48 shader units * 4 ops per cycle = 192 shader ops per clock
Xenos is clocked at 500MHZ *192 shader ops per clock = 96 billion shader ops per second.
(Did anyone notice that each shader unit on the 360’s GPU doesn’t perform as many ops per pipe as the rsx? The 360 GPU makes up for it by having superior architecture, having many more pipes which operate more efficiently and along with more bandwidth.)
Did Microsoft just make a mistake or did they purposely misrepresent their GPU to lead Sony on? The 360’s GPU is revolutionary in the sense that it’s the first GPU to use a Unified Shader architecture. According to developers this is as big a change as when the vertex shader was first introduced and even then the inclusion of the vertex shader was merely an add-on not a major change like this. The 360’s GPU also has a daughter die right there on the chip containing 10MB of EDRAM. This EDRAM has a framebuffer bandwidth of 256GB/s which is more than 5 times what the RSX or any GPU for the pc has for its framebuffer (even higher than G80’s framebuffer).
Thanks to the efficiency of the 360 GPU’s unified shader architecture and this 10MB of EDRAM the GPU is able to achieve 4XFSAA at no performance cost. ATI and Microsoft’s goal was to eliminate memory bandwidth as a bottleneck and they seem to have succeeded. If there are any pc gamers out there they notice that when they turn on things such as AA or HDR the performance goes down that’s because those features eat bandwidth hence the efficiency of the GPU’s operation decreases as they are turned on. With the 360 HDR+4XAA simultaneously are like nothing to the GPU with proper use of the EDRAM. The EDRAM contains a 3D logic unit which has 192 Floating Point Unit processors inside. The logic unit will be able to exchange data with the 10MB of RAM at 2 Terabits a second. Things such as antialiasing, computing z depths or occlusion culling can happen on the EDRAM without impacting the GPU’s workload.
Xenos writes to this EDRAM for its framebuffer and it’s connected to it via a 32GB/sec connection (this number is extremely close to the theoretical because the EDRAM is right there on the 360 GPU’s daughter die.) Don’t forget the EDRAM has a bandwidth of 256GB/s and its only by dividing this 256GB/s by the initial 32GB/s that we get from the connection of Xenos to the EDRAM we find out that Xenos is capable of multiplying its effective bandwidth to the frame buffer by a factor of 8 when processing pixels that make use of the EDRAM, which includes HDR or AA and other things. This leads to a maximum of 32*8=256GB/s which, to say the least, is a very effective way of dealing with bandwidth intensive tasks.
In order for this to be possible developers would need to setup their rendering engine to take advantage of both the EDRAM and the available onboard 3D logic. If anyone is confused why the 32GB/s is being multiplied by 8 its because once data travels over the 32GB/s bus it is able to be processed 8 times by the EDRAM logic to the EDRAM memory at a rate of 256GB/s so for every 32GB/s you send over 256GB/s gets processed. This results in RSX being at a bandwidth disadvantage in comparison to Xenos. Needless to say the 360 not only has an overabundance of video memory bandwidth, but it also has amazing memory saving features. For example to get 720P with 4XFSAA on traditional architecture would require 28MB worth of memory. On the 360 only 16MB is required. There are also features in the 360's Direct3D API where developers are able to fit 2 128x128 textures into the same space required for one, for example. So even with all the memory and all the memory bandwidth, they are still very mindful of how it’s used.
I wasn’t too clear earlier on the difference between the RSX’s dedicated pixel and vertex shader pipelines compared to the 360s unified shader architecture. The 360 GPU has 48 unified pipelines capable of accepting either pixel or vertex shader operations whereas with the older dedicated pixel and vertex pipeline architecture that RSX uses when you are in a vertex heavy situation most of the 24 pixel pipes go idle instead of helping out with vertex work.
Or on the flip side in a pixel heavy situation those 8 vertex shader pipelines are just idle and don’t help out the pixel pipes (because they aren’t able to), but with the 360’s unified architecture in a vertex heavy situation for example none of the pipes go idle. All 48 unified pipelines are capable of helping with either pixel or vertex shader operations when needed so as a result efficiency is greatly improved and so is overall performance. When pipelines are forced to go idle because they lack the capability to help another set of pipelines accomplish their task it’s detrimental to performance. This inefficient manner is how all current GPUs operate including the PS3's RSX. The pipelines go idle because the pixel pipes aren't able to help the vertex pipes accomplish a task or vice versa. Whats even more impressive about this GPU is it by itself determines the balance of how many pipelines to dedicate to vertex or pixel shader operations at any given time a programmer is NOT needed to handle any of this the GPU takes care of all this itself in the quickest most efficient way possible. 1080p is not a smart resolution to target in any form this generation, but if 360 developers wanted to get serious about 1080p, thanks to Xenos, could actually outperform the ps3 in 1080p. (The less efficient GPU always shows its weaknesses against the competition in higher resolutions so the best way for the rsx to be competitive is to stick to 720P) In vertex shader limited situations the 360’s gpu will literally be 6 times faster than RSX. With a unified shader architecture things are much more efficient than previous architectures allowed (which is extremely important). The 360’s GPU for example is 95-99% efficient with 4XAA enabled. With traditional architecture there are design related roadblocks that prevent such efficiency. To avoid such roadblocks, which held back previous hardware, the 360 GPU design team created a complex system of hardware threading inside the chip itself. In this case, each thread is a program associated with the shader arrays. The Xbox 360 GPU can manage and maintain state information on 64 separate threads in hardware. There's a thread buffer inside the chip, and the GPU can switch between threads instantaneously in order to keep the shader arrays busy at all times.
Want to know why Xenos doesn’t need as much raw horsepower to outperform say something like the x1900xtx or the 7900GTX? It makes up for not having as much raw horsepower by actually being efficient enough to fully achieve its advertised performance numbers which is an impressive feat. The x1900xtx has a peak pixel fillrate of 10.4Gigasamples a second while the 7900GTX has a peak pixel fillrate of 15.6Gigasamples a second. Neither of them is actually able to achieve and sustain those peak fillrate performance numbers though due to not being efficient enough, but they get away with it in this case since they can also bank on all the raw power. The performance winner between the 7900GTX and the X1900XTX is actually the X1900XTX despite a lower pixel fillrate (especially in higher resolutions) because it has twice as many pixel pipes and is the more efficient of the 2. It’s just a testament as to how important efficiency is. Well how exactly can the mere 360 GPU stand up to both of those with only a 128 bit memory interface and 500MHZ? Well the 360 GPU with 4XFSAA enabled achieves AND sustains its peak fillrate of 16Gigasamples per second which is achieved by the combination of the unified shader architecture and the excessive amount of bandwidth which gives it the type of efficiency that allows it to outperform GPUs with far more raw horsepower. I guess it also helps that it’s the single most advanced GPU currently available anyway for purchase. Things get even better when you factor in the Xenos’ MEMEXPORT ability which allows it to enable “streamout” which opens the door for Xenos to achieve DX10 class functionality. A shame Microsoft chose to disable Xenos’ other 16 pipelines to improve yields and keep costs down. Not many are even aware that the 360’s GPU has the exact same number of pipelines as ATI’s unreleased R600, but to keep costs down and to make the GPU easier to manufacture, Microsoft chose to disable one of the shader arrays containing 16 pipelines. What MEMEXPORT does is it expands the graphics pipeline in more general purpose and programmable manner.
I’ll borrow a quote from Dave Baumann since he explains it rather well.
“With the capability to fetch from anywhere in memory, perform arbitrary ALU operations and write the results back to memory, in conjunction with the raw floating point performance of the large shader ALU array, the MEMEXPORT facility does have the capability to achieve a wide range of fairly complex and general purpose operations; basically any operation that can be mapped to a wide SIMD array can be fairly efficiently achieved and in comparison to previous graphics pipelines it is achieved in fewer cycles and with lower latencies. For instance, this is probably the first time that general purpose physics calculation would be achievable, with a reasonable degree of success, on a graphics processor and is a big step towards the graphics processor becoming much more like a vector co-processor to the CPU.”
Even with all of this information there is still a lot more about this GPU that ATI just simply isn't revealing and considering they'll be borrowing technology used to design this GPU in their future pc products can you really blame them?
Site
http://dpad.gotfrag.com/portal/story/35372/?spage=9
Acho que já tinha postado o texto. Leiam tudo e depois tirem as vossas conclusões. Não se compara a placa da 360 com a placa da PS3. Leiam o que está em inglês leiam tudo. Quem percebe de hardware (mesmo que não pereba eu expliquei o mais importante) vê a diferença abismal.
(É + Inglês, mas pronto.)
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