Epic's Fergusson: Xbox 360 'Approaching Upper End' Of Visual Potential

[MikeB]

Squilliam said:

Insanestalker2 said:

Squilliam said:

WTF! Lol, I just reread this. It doesn't make any sense.

Total Ram - 512 mb unified + 10mb fast EDRAM for the frame buffer which means realistically that ram is worth more than the 522mb indicates. Furthermore theres a hardware tesselator which hasn't been used which can save at least 20mb of video ram (Very conservative)

The PS3 has about 5% less ram once you add the EDRAM and take into account the higher OS useage. Then you have to contend with the fact that the ram isn't unified so can't be used as flexibly. Thats ignoring the tesselator btw.

Thats why a PS3 engine is an easy fit into the Xbox 360 architecture due to the small size advantage for the Xbox 360 memory pool. 

 

I don't know where you are getting the 5% less ram from, is it comparing total ram, or ram that the gpu can use. Total ram would be around 2%. Also if it is gpu dedicated ram then the ps3 is 49% (256ps3,522xbox360), which is a 1% change from 50%. Granted I don't know much about the tesselator and I don't know much about how much work load the cell processor can take off of the gpu. I guess this puts my statement earlier as "wrong" since I don't know enough about either.

 

Memory pool Xbox 360 = 512 + 10 - 14 = 508 mb (System + ED ram - OS usage)

Memory pool PS3 = 512 - 30 = 482 mb (System - OS usage)

Therefore the Xbox 360 has 5.1% more ram available.

In terms of efficiency the Xbox 360 software on the system side uses less ram due to the overhead of utilizing more cores on the PS3. As SPE coding requires more lines of code as well the overall memory usage of the PS3 for the same code is higher.

 

 

The EDRam is another step in the 360 architecture and cannot be added to the main ram like that. The EDRam's small size is an important limiting factor. The main use of EDRam is adding effects like AA and HDR while maintaining good framerates, sadly the EDRam is too small in higher resolutions, it does not fit even 720p + AA so devs resort to tiling which greatly diminishes potential.

Also the PS3 has a default harddrive, think of this as virtual memory. Streaming data from Blu-Ray disc and the default harddrive, the PS3 provides higher memory bandwidth to the media next to its much better internal memory bandwidth as well as far more data storage (potential for more varierty of data and/or higher quality data). The comparison is therefore misleading, look at the NeoGeo which had very limited system memory, but the console could achieve much more with regard to gaming than PCs of its time which had many mulitple times the amount of system memory.

Just some factors to take into consideration.