Taking the Surface Tour

Moving away from the ports and looking inwards, we take a look at some of the ICs and other devices present on the Xbox 360's motherboard.

The Xbox 360's OS and other necessary software is loaded in the 128Mb (16MB) NAND Flash device that's on the motherboard:

Originally we assumed the chip below was a TV encoder, but we've since found out that the TV encoder on ATI's Xenos GPU is identical to what is on the ATI Radeon X1000 series of PC graphics cards - meaning the Xbox 360's TV encoder is located on the Xenos GPU itself and makes use of ATI's Xilleon display engine.

If it isn't the TV encoder, then what is this mystery chip? We haven't been able to find the physical interface for the Ethernet port, so it is possible that the 100Mbit PHY is located within this chip, as well as the audio codec, both of which would make sense given its location on the motherboard (within close proximity to the AV cable connector). In addition to those two options, it is possible that this chip may house whatever DRM technology is used in the Xbox 360.

Next up we've got a single 64MB Samsung GDDR3 memory device from the Xbox 360's motherboard; there are a total of 8 of these chips on the motherboard, adding up to the system's full 512MB of unified system memory. The part number on the chip indicates a 700MHz operating frequency, with a 1.4Gbps/pin data rate, which is exactly what is specified by Microsoft:

The Motherboard's Ports Up Close and Personal with the CPU, GPU and... Yonah?
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  • Bally900 - Monday, June 02, 2008 - link

    Hi everyone.
    I have removed the gpu clamp from the bottom of the xbox motherboard, there seems to be some blown components, therefore I was hoping there was some good photo's of the motherboard with gpu xclamp removed?? Any help is v much appreciated.
    Reply
  • Kensei - Sunday, November 20, 2005 - link

    FYI... have a look at last Friday's WSJ article on the XBox 360. Lots of interesting information on how the XBox is made in China.

    Kensei
    Reply
  • Clauzii - Sunday, November 20, 2005 - link

    I think there is too much ´splatter´ on that GPU-tingy.. Reply
  • agnot - Saturday, November 19, 2005 - link

    Why was Hypertransport classified as a serial bus? As implemented on K8, it's a 16-bit wide data bus in each direction, so 32 pins in total for data per HT link. Moreover it doesn't have any SERDES logic (serializer/deserializer that converts parallel data to serial data and vice versa). This gives Hypertransport a latency advantage over serial links that require these extra steps, and low latency, as I understand it, was one of the main concerns when developing Hypertransport. Reply
  • segfault7 - Sunday, November 20, 2005 - link

    I wondered the same thing. Althought the author is confused on this point he does make a nice comparison between serial and parallel buses.

    "Note the clear definition of the traces the clean routing, to the point where you can count the individual data, address and clock lines:"

    This statement also is a little misleading since every serial bus that I have looked at (PCIe/SATA/IB) dervives the clock from the data stream. Additionally the address and data are typically sent on the same lines in the form of a packet.

    Good article. I'm looking forward to the flurry of xbox 360 hacking that is about to ensue.
    Reply
  • TheInvincibleMustard - Friday, November 18, 2005 - link

    I like the inclusion of the little thumbnails with red circles on them. It's a simple yet effective method of communicating just where something is on the motherboard. Props to whoever proposed that idea!

    -TIM
    Reply
  • icube - Friday, November 18, 2005 - link

    I'm pretty sure that mystery chip is the custom hdtv encoder/scaler created by the old WebTV team for the xbox360. Maybe it has some other functions as well though.

    See: http://blogs.mercurynews.com/aei/2005/08/a_walk_th...">http://blogs.mercurynews.com/aei/2005/08/a_walk_th...

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    Robbie Bach, the chief Xbox officer, even came down for a visit once to make sure all the WebTV folks stayed aboard and helped with the 360. He knew that they had a lot of options in the valley. One of the chips they designed was a TV encoder that would support the TV-side of the system.

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    Reply
  • yacoub - Friday, November 18, 2005 - link

    That comparison between serial and parallel on the last page was very informative. Sometimes a picture really does speak for a volume of words. Very cool. Reply
  • mlittl3 - Friday, November 18, 2005 - link

    This is a great breakdown of a very custom, sophisticated motherboard. I was wondering if Anandtech could do the same thing with another custom, sophisticatd moetherboard...the one in the Powermac G5. That's got to have some pretty cool features also. Reply
  • stmok - Friday, November 18, 2005 - link

    I'm always curious...We can modify the current Xbox 1 to run Linux...How about the 360? :) Reply

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