Both Sony and Microsoft went with slightly tweaked, off-the-shelf graphics chips for their consoles. The Xbox 360's Xenos GPU, produced by ATI, is similar to the Radeon X1800 XL. The PS3's nVidia RSX is virtually identical to the GeForce 7800 GTX. Both chips have identical specifications to their PC gaming counterparts. Naturally, you'd think the Xbox's chip would outperform the Playstation's. In real world tests, it doesn't.
|The PS3's graphics look washed and blurry in the original Assassin's Creed. From Techblog.com|
The PS3 actually has the more powerful CPU and GPU of the two consoles. So why does it tend to look worse, or struggle with certain games like Oblivion? It's counter intuitive.
|Crysis 2 is another example of where the PS3 falls short. Notice the missing details. From Androidguide.ru|
The Xbox dynamically allocates it's memory usage. Basically, if the CPU only needs 128mb of RAM, then the GPU has the rest. It uses these for textures and other things it needs to store and quickly retrieve. The more memory the GPU has, the bigger the textures it can store. The bigger the textures, the better the image.
|The Xbox 360 shares it's RAM between the GPU and CPU.|
So how much performance does a graphically intense game of the period use? I loaded up Flight Simulator X on the PC and calculated it's ram usage to be about 650mb evenly split between GPU and CPU. Keep in mind that PC isn't an embedded system. So about 50mb of GDDR are likely being used for other stuff that's running in the background. Namely the desktop.
That's not the say that the PS3 wouldn't benefit from more memory, though not necessarily for graphics. The Cell is a very powerful CPU hampered by a limited amount of system RAM. Our quick test shows that a period game easily consumes more CPU memory than the PS3 has. That's not including all the other things Windows does in the background.
|In recent third party games, the differences are much less noticeable. From Attackofthefanboy.com|
The PS3 is very much a system built on compromises. At launch, it was already going for $600, which Sony was selling at a loss. Estimates peg actual manufacturing costs to be over $800. While the addition of pricey Blu-ray was heavily criticized, that eventually paid off in spades for Sony. The problem lies with other parts within the system.
Sony used Rambus XDR memory, which is notoriously expensive. It's faster than the Xbox's GDDR3 on paper, but real world performance improvements are dubious at best. On top of that, they insisted on full hardware PS2 backwards compatibility. The original PS3s literally had a Playstation 2 shoehorned inside them. Had they cut that from the beginning and focused on adding more memory, they would have had a better console.
That still doesn't explain why the PS3 doesn't look as good as the Xbox 360. The real answer is much more simple. At the time, nVidia and ATI were fighting a fierce arms race to build the best GPU. There were two schools of thought going at the time. One was to build a chip optimized for raw power. A GPU that, clock for clock, could produce higher frame rates and higher resolutions than its competitors. The other idea was to build a chip that focused it's power on producing the sharpest and most vibrant images. nVidia went with speed, ATI went with image quality.
|Uncharted 3 shows was a properly programmed game can do with the PS3. From Gamersyde.ca|