Xbox 360 Hardware limits

Veebs


Hi,

I've been searching around for the answer to two questions but have had no luck. Firstly how much system memory can an Xbox360 XNA game actually use. I know the executable size is limited to 50Mb just like Arcade games, but with procedural techniques you could still use up lots of physical memory.

Secondly how many cores are available on the xbox 360 for use to XNA developers. Are two cores powered down so we in effect only have two hardware threads or can we use all six. Judging by the fact the fan is not on 'noisy';) I assume it is the former.

Many thanks!

Jon Watte


There are 3 cores, each of which is hyper-threaded, so there are 6 hardware threads. Of those, the XNA runtime has chosen to reserve 2, so you get 4 hardware threads for yourself. It appears that you get one thread for core 0, 1 thread from core 1, and both threads from core 2.

The Xbox has 512 MB of RAM, which is shared between graphics, sound, game state, etc. Managed resources don't necessarily need to be duplicated in memory, though, because there's no risk of device loss/reset. You can do the math yourself based on that. (I would assume that some amount of space is used by the XNA framework, too -- say 32 MB for a conservative estimate)

If you really want to know, you could create a linked list, and add class instances size 4000 bytes successively to that list, until you run out of memory. Count how many you could create before the exception.

Michael Klucher - MSFT

Veebs wrote:

I know the executable size is limited to 50Mb just like Arcade games, but with procedural techniques you could still use up lots of physical memory.

This is a requirement for Xbox Live Arcade games and not games you personally develop with XNA Game Studio Express. If you had an agreement to publish the game it would be a concern but each game can have up to 2GB of space to delpoy content and your game too .