Currently, as of SDK 1.60, the PS3 operating system takes up 52 MB of main memory (a reduction of 12 MB since launch) and 32 MB of graphics memory (84 MB total). As a comparison, the Xbox 360 still only uses 32 MB of shared memory for all its system utilities.
As of SDK 1.60, developers can use standard PS3 message dialogs at no extra cost. The standard on-screen keyboard still requires 7MB of memory.
Developers can now choose to support the Remote Play functionality (which allows players to play their PS3 titles on their local wireless LAN using their PSP. Remote Play requires 8MB of memory to be allocated to it.
The various utilities providing saving, loading, and reading off the hard disk now require no more than 5MB of memory to be used.
8MB of memory is required for the online startup utility. This includes both supporting online play, and is a requirement for any of the other Network Platform (NP) utilities. There are several NP utilities, but we will only address the most important one next.
Full support of the NP Friend List utility is currently a staggering 24MB of extra memory (on top of the 8MB needed for the startup). This utility provides the support of the NP friends list, allowing players to add, remove, block and communicate with their friends along with the corresponding GUI interface. The extraneous demand on memory has been met with with concern from developers. Since this is just the first iteration of the utility, Sony has vowed to reduce the memory impact of the utility to something more manageable (20MB is the rumored target for the next major release expected in late May early June).
Video chat (supporting up to 6 concurrent users) requires 26MB of memory, while voice chat (supporting up to 12 users) requires 8MB. The utility allowing for in-game microphone configuration is also 8MB.
Finally, developers can choose to support an integrated web browser. The memory cost for a web browser can vary from around 40MB to 90MB+, depending on the web sites being browsed, and the number of windows and tabs used.