There has been discussion of why the PS3 OS footprint is so large. Truth is, the PS3 OS does not use all the memory that has been given to it...in fact no where close. Sony have instead put aside a large amount of memory (84mb) for future applications - what these mysterious applications might be, is unknown.
Why does Sony need to put aside so much memory now if they are not using it? Well if they didn't and needed it in the future, then older games would not be able to run, as there wouldn't be enough memory.
So what is the OS memory footprint? Well first, the base memory footprint of the PS3 OS in main memory has been reduced from 56 MB to 52 MB. These values will lead to some confusion, as we've previously reported that the memory footprint was 64 MB. 8MB of memory was given back to developers sometime before Christmas, and now a further 4 MB has been returned. Currently, as of SDK 1.60, the PS3 operating system takes up 52 MB of main memory and 32 MB of graphics memory (84 MB total).
This article goes on to list possible applications and their current memory usage, which will be reduced by Sony as time goes on...but some of the listed features are promising, such as a unified friends list ingame, an intergrated web browser, and video chat ingame. But whether developers choose to use these applications is open to them, since the memory footprint is rather large.
Please read on.