First lets start off with the basic RAM structure:
360: The 360 has 512mb unified RAM which isn't as powerful because everything is stored in one pool.
Its not as powerful but it is more flexible. devs can designate memory to different tasks in what ever way they see fit, allowing them to optimize memory usage. theres also no inherent performance hit by doing it.
PS3: The PS3 has several pools of RAM. One RAM pool is 256mb GDDR3 which is the type of RAM that the 360 uses. The other pool is 256mb XDR RAM which is faster than GDR3, approximately 12x faster. Developers can also take RAM from both pools if they need too, making it flexable between dedicated and shared.
true. but its less flexible. if a dev want to use more texture memory than the 256MB GDDR3, they need to go through the cell and into the XDR ram. doing this causes a performance hit since the CPU is put under more burden and the XDR ram has to slow down. theres no such extra burden on the 360.
Next lets talk about the speed of the RAM. Most people think that the speed of RAM is useless because it doesn't process data. This is why they are wrong:
360: The 360 uses GDDR3 RAM which is standard in most computers now days. GDDR3 is faily fast RAM but not the fastest.
Indeed its not the fastest. but the speed of the ram doesent have a huge baring on the performance of a machine and games dont seem to be that sensative to it. more ram is always better than faster ram (within reason of course).
PS3: One of the PS3s pools has XDR RAM which is 12x faster than GDR3. The speed of the RAM does in fact matter. The faster the RAM, the faster textures and effects can be accessed and used. This means that the PS3s one pool is much better than the 360s unified.
faster ram does not compensate for more ram. if sony replaced that XDR ram with 512MB of gddr3 (which would be cheaper) and the PS3 had 768MB in total then it would be alot better off. XDR is great stuff (i wanted it in my PC but it wasnt available at the time) but if its a choice between a gig of XDR or 2 gigs of ddr2 or gddr3 then the 2 gigs wins every time. however it is alot faster than the 360s stuff and, as long as devs dont use it for texture data to share with the RSX, it does offer an advantage over the 360. not a hige one mind but it does help.
The processor:
360: The 360s processor does not do anything to help out the RAM.
im not sure what u mean here. are u saying that the 360s CPU does not assist with graphics? if u are then u are incorrect. although the 360 has unified shaders, it doesent mean that devs can just throw all graphics at it. CPUs still have to do there fair share of the work on the graphics front. CPUs have been rendering graphics long before the cell came along. before the advent of the geforce, the CPU actually did the lions share of the work. the graphics chip just added a few effects and smoothed some stuff out. hardware T&L moved alot of the work from the CPU when the geforce 256 came along but CPUs still do their fair share of the graphics load.
PS3: The Cell processor has the ability to run RAM functions such as effects and textures. By doing this developers can take off a great deal of load off of the RSX, giving them more room to work with.
as above, every CPU can take a load off the GPU. do note though that GPUs are a hell of alot better at graphics than any CPU, and that includes the cell. compared to a GPU, the cell is inefficent at running graphics data. it is arguably more suited to the task than a more traditional cpu but its still wasteful. also having the cell render graphics greatly negates any other advantages it might provide since it has a greater burden on it.
Accessibility:
360: Due to its old and well known form of RA, the devs can use the 360 to its full limits.
PS3: The PS3s hard infastructure, although more powerful, is giving devs a hard time, but that will change when they get the feel for the tech.
There you go!!! ;)
snorlaxmaster
my bits in red.
basically on paper the PS3s ram setup looks better. but in the real world this doesent look to be the case at all.
with the 360, the key word of its design is flexibility. this in itself means that devs can get more out of it quicker and refine its usage more for a game. theres no performance hit by going over a certain amount of memory for textures or vertex data so devs can do whatever the hell they want. its the same with its GPU (a bit off topic i know) want 48 pixel shaders and let the CPU do the vertex shader work? go ahead. want to do it the other way around? go nuts. (note devs would never actually do that as it would cause a huge performance hit on any platform...but u get the idea).
the PS3 is far more fixed in its nature. if u go over 256MB for graphics data then there will be a performance cost. if u have alot of vertex shader data that needs to be processed but very little pixel shader data then the pixel shaders are doing zip. now if u can build a game that, by design, plays to the PS3s strengths then u can get more out of it compared to the 360. but ure choices are also more limited.
thats not to say that the PS3s design is terrible or anything. even when devs dont play to its strengths, it still does the job for the most part. its just not an all conquering setup. 1 big bank of 768MB of gddr3 memory (or maybe 2 seperate banks, 512 for graphics data and 256 for other stuff) would have allowed the PS3 to do alot more on the ram front.
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