The Xbox 360 Chipset

As we mentioned before, the Xbox 360's North Bridge is integrated into the GPU, similar to most PC chipsets with integrated graphics.  The North Bridge is on the main die of the GPU and shares the same 128-bit GDDR3 memory controller that the graphics core uses to access the Xbox 360's 512MB of memory.  This bus runs at 1.4GHz offering just over 22GB/s of bandwidth to main memory. 


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On the other side of the North Bridge there's the CPU's FSB interface, which offers  10.8GB/s of bandwidth in each direction (21.6GB/s total).  You can see the serial FSB laid out in the image below:


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The North Bridge also features a 500MB/s interface to the Xbox 360's South Bridge, which was designed by SiS (pictured below).


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Once again, you don't see any non-Microsoft logos on any of these chips.  It's clear this time around who the IP belongs to.  The South Bridge is responsible for communication with the audio codec, storage devices, USB ports, controllers, and any other I/O devices. 

The Xbox 360 GPU The Wireless Controllers
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  • Questar - Wednesday, November 16, 2005 - link

    " We roughly estimated the power of the Xbox 360 GPU to be similar to that of a 24-pipeline ATI R420 GPU."

    What do you base this on?
  • Snuffles - Wednesday, November 16, 2005 - link

    From the article:

    quote:

    Unfortunately, we have yet to hear from Microsoft if this means that all games must be internally rendered at 1280 x 720 or if they can be rendered at a lower resolution and upscaled later on. There have been discussions involving at least one Xbox 360 game (Project Gotham Racing 3), rendering internally at a lower resolution and having the Xbox 360's TV encoder upscale it to 720p.



    The reason for this can be found on Bizarre's Forums:

    quote:

    For those wondering why this information would be true, here's the technical reason for why the game would probably be running at 1024x600 interally. On the Xbox 360, there is a thing called DRAM which serves as the framebuffer for the image. It has 10MB of DRAM, which means it can store a 10MB image, and the advantage is that it can render that image very fast (this is what gives the Xbox 360 it's "free" AA capability). Now the thing is, that 10MB can only store a full HD image (1280x720 and above) WITHOUT Anti-aliasing. So, they have a system where games can split a frame into seperate sections called tiles so that each tile would fit into that 10MB of DRAM. However, tiling is something that may have to be planned for early in the game's development, and the final Xbox 360 development kits (which were the only ones to include the DRAM) were only made availible a few months ago. In turn, Bizarre may not have had time to build tiling into the game, and therefor wouldn't have been able to enable anti-aliasing when it's running at HD. So instead, what they've likely done is lowered the resolution to 1024x600 and enabled 2xAA (which coincidentally fits into the 10MB DRAM buffer perfectly), which allows them to use anti-aliasing without adding tiling into the game.



    http://www.bizarreonline.net/forum/viewtopic.php?t...">Link

    This essentially means that all later games which are built from ground up to include tiling, will feature free AA and a native 720p resolution. PGR3 had to go this route, because of lack of time with the final devkit and time restraints in order to make launch.
  • Questar - Wednesday, November 16, 2005 - link

    " We roughly estimated the power of the Xbox 360 GPU to be similar to that of a 24-pipeline ATI R420 GPU."

    What do you base this on?
  • Questar - Wednesday, November 16, 2005 - link

    " We roughly estimated the power of the Xbox 360 GPU to be similar to that of a 24-pipeline ATI R420 GPU."

    What do you base this on?
  • nourdmrolNMT1 - Wednesday, November 16, 2005 - link

    these screws are NOT torx screws. these are Hex Heads.

    you aint gunna be using a torx driver to remove them. there is a difference, and the T7, T8 are what comfirm this. Torx have 5 points, these have 6, and are deffinately completely different from torx as they are much harder to strip out.

    no, its Dice as proven above.
  • bldckstark - Wednesday, November 16, 2005 - link

    From wikipedia.com search for torx -->

    quote:

    Torx is the trademark for a type of screw head characterized by a 6-point star-shaped pattern (in the same way that flatheads, Phillips, Allen, and Robertson have flat, ×-shaped, hexagonal, and square tips, respectively). People unfamiliar with the trademark generally use the term star, as in "star screwdriver" or "star bits." The generic name is hexalobular internal driving feature and is standardised by the International Organization for Standardization as ISO 10664.


    A hex head is usually referred to as an Allen bolt or the infamous Allen wrench.

    And as I posted earlier, from dictionary.com, the definition of dice is as follows --> A small cube marked on each side with from one to six dots, usually used in pairs in gambling and in various other games.

    The item referred to in this in plural form is dies.
  • Ruark - Wednesday, November 16, 2005 - link

    "You can now lift up the motherboard out of the metal chassis."
    Less awkward, "You can now lift the motherboard out of the metal chassis."

    "Three star bit screw drivers in the following sizes: T6, T7 and T12"
    Is a three star ranked a little lower than a four star? ;) At first glance, I thought this was certainly a secure method of attachment if a screw driver with a three pointed star tip was needed. Torx, torx, torx!

    "After two corners have been lifted, the rest of the clamp springs loose and can easily be removed by hand."

    As these are not the small cubes used for gaming, the plural should be dies.
  • Ruark - Wednesday, November 16, 2005 - link

    "Using your start bit screw drivers, remove the silver screws. . ."
  • PhoneZ - Thursday, November 17, 2005 - link

    "..START bit screwdriver.."? Or is that supposed to be star? Since we feel the need to correct people.
  • Live - Wednesday, November 16, 2005 - link

    So how do we overclock it?

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