What are the quick and dirty system specs?
3.2 GHz PowerPC processor with 3 cores
ATI custom graphics chip
512MB GDDR3 Unified System Memory
10MB embedded DRAM
12X DVD drive
20GB HDD
3 processor cores?
Yes, Xbox 360 will have three processor cores, each running at 3.2 GHz. On top of that, each processor is capable of running two threads a piece, meaning that the console will be able to handle six instructions simultaneously. How difficult it is for developers to code for the system is unknown, though it seems quite obvious now that Microsoft's XNA project was made for a very specific purpose.
Who's supplying the hardware?
IBM is supplying the main processors while ATI will supply the graphics chip.
Tell me about the graphics chip...
Xbox 360's GPU is based on ATI's next-generation graphics chip, putting it at least one generation beyond its current X850 card for PCs.
The GPU runs at 500MHz and features 48 shader units, which are not directly comparable to traditional pixel pipelines. Rather than having pixel and vertex shaders work as separated elements like on current PC video cards, each shader unit can perform either pixel or vertex shading as necessary. This allows the system to move performance to where it's needed, either for more effects or more raw geometry rendering.
Basically, it's fast as all hell.
How much RAM will Xbox 360 have?
The system will have 512MB of GDDR3 unified system memory and 10MB of embedded DRAM for the framebuffer.
What about video RAM?
The Xbox 360 make's use of a shared memory architecture. That means that the system's 512MB of RAM will be used for graphics and texture memory as well as things like sound, animation source and of course, the actual game code itself.
While the majority of the graphics data will be housed in the shared system RAM, like textures and the like, the video framebuffer will use NEC's dedicated embedded DRAM technology. Long story short, by embedding the framebuffer RAM directly onto the graphics chip, Xbox 360 will be able to perform post-processing features much more quickly, like anti-aliasing and motion blur. The Xbox 360 has 10MB of embedded DRAM.
Will Xbox 360 have a dedicated physics processor?
No, though each PowerPC processor core has its own 128-bit vector math unit, so these could be used for physics calculations.
Will Xbox 360 be backwards compatible?
The problem with backwards compatibility is that the original Xbox ran on an nVIDIA graphics processor. When software makes calls to a chipset to produce visuals it uses code specific to that hardware. Xbox 360 runs on an ATI graphics chip meaning that code from last generation games will need to be recompiled or emulated in order to work on the system. Does this mean that consumers will have to chuck their beloved Xbox libraries? Not necessarily. There is a chance that Xbox 360 will have the ability to