以下为转贴
－－－－－PS3开发机GPU表现不容乐观，CELL芯片本地读写速度惨不忍睹－－－－－再缩水．．．就成6600了
这是索尼自己公布的，国外网站已经确认，无需质疑
加（）的为我的话，此为转贴 转贴者请标明LU新闻出处．
近日，索尼在日本召开了一次关于PS3开发状况的内部会议（网站已经公开数据表格照片和与会内容），会上索尼公布了一系列有关PS3开发硬件的详细资料。但根据目前的情况来看，PS3开发硬件所使用的GPU（图形芯片）只能发挥出理论值的2/3左右，而CELL芯片的表现也很难让人感到满意。
索尼目前有两个版本的PS3开发硬件，即我们所知道的CEB版和DEH版。早期的CEB版使用CBE芯片主存储器和南桥芯片上，南桥芯片再通过PCIe连接到NV4x芯片上。目前使用的DEH版依然使用了CBE芯片以及主存储器，唯一的区别就是用RSX芯片来代替原先的NV4x与南桥芯片的组合，因此，RSX也可以被看作是一种拥有南桥功能的图形芯片。
在随后的报告中显示，DEH开发机现在仍然无法达到索尼预期的工作性能，而DEH所使用的RSX芯片组主频目前只有420MHz、显存只有600MHz（比我的6600GT差点．．．比我以前的5200好点．．．），这比索尼原先公开的的官方规格（主频550MHz、显存频率700MHz）依然有一定差距。综合算来，PS3目前开发硬件的GPU速度大概只有理论值的2/3左右。
另外，RSX芯片主存储器的实际读、写速度（15.5GB每秒/10.6GB每秒）都比理论值（20GB每秒/15GB每秒）要低不少。CELL芯片的本地存储器写入速度仅为4GB/秒，而读取速度竟然只有令人诧异的16M每秒，如此巨大的数量级上的差异让几乎所有的与会者都难以相信自己的眼睛，场下顿时一片嘘声。而更糟糕的是，根据索尼公布的数据，RSX芯片目前每秒只能运算2亿7千5百万个三角形，这与Xbox 360每秒超过5亿个三角形的运算速度相比实在是让人惨不忍睹。
从目前的情况来看，PS3开发硬件所使用的图形芯片依然无法达到最佳状态，而CELL芯片的实际表现又让很难让人满意，而与微软为Xbox 360提供的开发工具相比，许多开发商都反映过PS3的开发工具不够友善。如果用将近2倍的价格却只能换来1/2的性能，这样的结果相信所有人都无法接受。好在现在离PS3正式发售还有几个月的时间，希望索尼能有所行动，尽快完善PS3的性能。
刚到家就看见这新闻．．．晕 这RSX的频率和我的6600GT差不多．．．多边形数量是360的一半．．．．
小鸟休福 快把你的MGS4移植吧．．．我不想买这东西．．．可能是我比较穷 买不起吧 呵呵 要骂我穷的快来骂吧 我买不起PS3这东西啊．．．
真心希望在11月发售的PS3 能超越XB360性能 还有5个月能改进（不过当时微软花了3个月时间还没解决个电源问题．．．这是事实啊．．．5个月，索尼能做什么？再延期？还是用5个月提升性能到XB360的两倍？延吧呵呵）
必尽大家等了1年了．很多人还为了你索尼和自己国家的同胞吵架，现在这会议．索尼是不是觉悟了．换种方式向拥护他的饭们道歉呢？如果是的话，我希望他永远忽悠下去（我同学看见这贴会不会不认我这朋友．．．）
这一年不应该是倒退的．
如果你要说 等出来了再说的话 那要想想了 这可是索尼自己发布的 这有没有可能是这个意思：现在不公布，将来出来了 落差太大 谁还会买？丑媳妇总要见公婆的嘛 前几天那些诸如“不在乎市场份额”的大炮们的言论，原来是在给自己找台阶下 所以．这次我是理解索尼的．虽然仍旧是强到逆天．．．
转贴 转贴而已．．．
下面部分来自TGFC译文
By Charlie Demerjian in Taipei: 星期日 04 六月 2006, 16:19
SOME VERY INTERESTING tidbits have emerged about the PS3 GPU during my flight to Japan yesterday. It seems like the second gen dev kits were running nowhere close to full speed or spec. How close were they? Fairly.
Documents shown to us on the trip showed that there were two versions, labeled 'CEB' and 'DEH'. The earlier CEB has a chip called CBE (yes, I know) connected to main memory and to a south bridge. The SB is then connected to a chip labled 'NV4x' over a PCIe link. The upcoming version DEH has the CBE and main memory, but the NV4x/SB combo is replaced by the RSX. If you wanted to know what makes RSX more than a GPU, it looks like it is SB functionality.
The slightly more curious bit, encouraging and disturbing at the same time, is the current state of RSX. The disturbing part is that the slide I was shown had "Current DEH's aren't final spec or speed" in bold letters. Speed, OK, but not final spec at this point in time leaves precious little room for debugging before the console release. On a different note the current ones are running the RSX core at 420MHz with 550 expected for launch. Memory is set at 600MHz with 700 hoped for as final.
It looks like SoNVidia is most of the way there with RSX development, 80% of the clock, more for memory. One more spin, most likely another round of dev kits, and the code monkeys will know what they are facing. µ
首先是即将到来的新版开发机~按计划应该是最终版了~但RSX速度只有420MHZ，不是原计划的550MHZ; XDR内存速度为600MHZ，不是原计划的700MHZ；SONY特别注明该版本开发机依然不是最终版，但问题是如果现在还不拿出最终版开发机，游戏开发商根本就没有时间做最后调试工作~~WELL，那些代码民工们将会知道他们面对的是什么~~
PS3 hardware slow and broken
In words and pictures
By Charlie Demerjian in Taipei:
AFTER BREAKING THE news to me about PS3 RSX speeds earlier on the flight to Japan, my row-mate said 'if you think that's interesting, wait till you see this. Cell is hurting, badly'.
For those of you that believe in religions with karmic tendencies, scoops like this meant one of two things, the wings of the plane are about to fall off and I am going to die in a fiery ball, or worse yet, the movie selection will be worrisome. Cell memory access appears to be broken, RSX has half the triangle setup rate of the ATI chip in XBox360, and the true horror, Big Momma's House 2 and a Queen Latifa movie.
With the movie selection still making my brain throb from the glances I caught, I furiously took notes on what the source was saying. He started out saying that the RSX can only write about half as much vertex data as it can fetch, not an ideal situation by any stretch, but survivable.
Then came the horrible news, RSX appears to be limited to setting up 275 Million triangles/second, anemic compared to the 500+ million in XBox360. When asked about this apparent thumping dished out by MS, the reply from one notable ISV relations boffin was a terse 'What a Piece of Junk'. Talk about a steak in the heart.
Half the triangle setup capability in the PS3, could things get worse? Yes, far far worse, how about another disparity of three orders of magnitude? No, I am not joking, looking at Sony's own figures, Cell appears to be pretty badly broken.
For main memory, it looks like Cell has about 25GBps of main memory bandwidth, and RSX is about 15-20GBps. Achievable bandwidth is between about two thirds of that and nearly 100%, clearly the elves in the caves surrounding Rambus central did something right with XDR. That is the happy news.
For local memory, the measured vs theoretical bandwidth is missing, I wonder why? RSX is at a solid 22.4GBps for both read and write, good job there green team. Then comes the blue team with Cell. Local memory write is about 4GBps, 40% of the next slowest bandwidth there. Then comes the bomb from hell, the Cell local memory read bandwidth is a stunning 16MBps, note that is a capital M to connote Mega vs a capital G to connote Giga. This is a three order of magnitude oopsie, and it is an oopsie, as Sony put it "(no, this isn't a typo...)".
If you can write at 250x the read speed, it makes Cell local memory just about useless. That means you do all your work out of main memory, and the whole point of local is, well, pointless. This can lead to contention issues for the main memory bus, and all sorts of nightmarish to debug performance problems. Basically, if this Sony presentation to PS3 devs shown to us is correct, it looks like PS3 will be hobbled in a serious way.
The next slide goes on to say "Don't read from local memory, but write to main memory with RSX(tm) and read it from there instead", and repeats the table numbers. This is very very bad. The number of times the presentation goes on to say that it is correct, and the lack of anything like "this will be fixed by production steppings, so take measures X, Y and Z" say to me that it is not a fixable snafu. Remember at E3 when I said that the PS3 demos there were object sparse? Any guesses why?
Someone screwed up so badly it looks like it will relegate the console to second place behind the 360. All the devs I talked to were lukewarm on the 360 architecture but universally negative on the PS3. Revelations like this go a long way to explain why you keep hearing about simmering problems from the Sony devs.
You end up with a console with half the triangle setup rate of the 360, a crippled CPU that is a bitch to program, and tools that are atrocious compared to the 360. To make matters worse, you have an arrogant set of execs telling us that twice the price is worth it for half the power, a year late. If it isn't already too late, Sony had better do something about this recto-cranial inversion or it may very well sink the console. µ
消息接连不断~RSX的多边形生成速度被限制在2.75亿/秒~远低于X360的5亿/秒……RSX问题不断，但更坏的消息来自内存，PS3 怪异的两种内存混合结构也有大麻烦~
先看图中主内存的带宽，恩，似乎还没有太大问题，实际带宽大约是理论值的2/3到100%; 然后再看看本地内存的读写带宽，RSX表现也尚可~~
但一到CELL，问题来了！写内存速度只有4G/S？这可是很不正常的速度；不过最后真正的大麻烦是CELL的本地内存读取带宽，居然只有16M/S……注意单位是MB/S不是GB/S！
很显然SONY在CELL的两种内存配合工作上遇到了大麻烦，下一张幻灯片也清楚的告诫开发者最好不要动用本地内存，应该和RSX共用主内存……
PPT上多次强调这个问题，但并没有说明这个问题能够被修正……
最后的总结就不翻译了，不说大家都知道是什么~~
[ 本帖最后由 ◤nitct◢ 于 2006-6-5 19:34 编辑 ] |
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发表于 2006-6-5 16:46:52
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