Motherboard: Difference between revisions

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(Created page with '(This page is riddled with speculation and extrapolation of information from dodgy sources, so take it with a grain of salt.) The Xbox 360 mainboard (or motherboard) has underg…')
 
imported>Tuxuser
 
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{{Cleanup}}
(This page is riddled with speculation and extrapolation of information from dodgy sources, so take it with a grain of salt.)  
(This page is riddled with speculation and extrapolation of information from dodgy sources, so take it with a grain of salt.)  


The Xbox 360 mainboard (or motherboard) has undergone a few revisions, as Microsoft has corrected mistakes or added/improved existing features.  
The Xbox 360 motherboard (or motherboard) has undergone a few revisions, as Microsoft has corrected mistakes or added/improved existing features.  


*Known revisions include:  
*Known revisions include:  
:*[[Xenon]] (Launch hardware)  
:*[[Xenon_(Motherboard)|Xenon]] (Launch hardware)  
:*[[Zephyr]] (Elite)  
:*[[Zephyr]] (Elite)  
:*[[Falcon]] (65nm Chipset revision)  
:*[[Falcon]] (65nm Chipset revision)  
:*[[Opus]]  
:*[[Opus]]  
:*[[Jasper]] (Onboard Memory_Unit)  
:*[[Jasper]] (Onboard Memory Unit)
:*[[Trinity]] (Slim)


== Details ==
== Details ==
The mainboard PCB has four layers (sources: [http://www.ccw.com.cn/notebook/pczx/sy/htm2005/20051028_16OMI.htm], [http://www.anandtech.com/video/showdoc.aspx?i=2414]), implying that the top and bottom layers (the ones we can see and probe) contain most of the signals. This is a good thing :)  
The motherboard PCB has four layers (sources: [http://www.ccw.com.cn/notebook/pczx/sy/htm2005/20051028_16OMI.htm], [http://www.anandtech.com/video/showdoc.aspx?i=2414]), implying that the top and bottom layers (the ones we can see and probe) contain most of the signals. This is a good thing :)  




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According to [http://www.ccw.com.cn/notebook/pczx/sy/htm2005/20051028_16OMI.htm these] [http://www.cdrinfo.com/images/uploaded/Xbox_Architecture_large.gif three] [http://en.wikipedia.org/wiki/Xbox_360#Hardware_specifications sources] the FSB is a serial bus with 16 differential pairs in each direction, and each pair runs at 5.4Gbit/s. This agrees with Microsoft's published bandwidth specification of 21.6 Gbyte/sec (10.8 Gbyte/sec each way, 16 bits/2 bytes at a time, 5.4 Gbit/sec per pair).  
According to [http://www.ccw.com.cn/notebook/pczx/sy/htm2005/20051028_16OMI.htm these] [http://www.cdrinfo.com/images/uploaded/Xbox_Architecture_large.gif three] [http://en.wikipedia.org/wiki/Xbox_360#Hardware_specifications sources] the FSB is a serial bus with 16 differential pairs in each direction, and each pair runs at 5.4Gbit/s. This agrees with Microsoft's published bandwidth specification of 21.6 Gbyte/sec (10.8 Gbyte/sec each way, 16 bits/2 bytes at a time, 5.4 Gbit/sec per pair).  


Looking at photos of the mainboard, we can see 40 pairs of carefully routed tracks between the CPU and GPU. 32 pairs (16 each way) + 8 clock/handshake/parity? pairs = 40 pairs.  
Looking at photos of the motherboard, we can see 40 pairs of carefully routed tracks between the CPU and GPU. 32 pairs (16 each way) + 8 clock/handshake/parity? pairs = 40 pairs.  


This very high frequency interface will make probing and snooping on the bus extremely difficult, which is unfortunate because the Xbox1 security was compromised in part by a FSB bus snoop done by bunnie. At this frequency, the (relatively) simple task of attaching probe wires to the FSB will change the impedance seen on the bus by the FSB PHYs and cause the bus to fail to work correctly (look at eye diagram...). It might still be possible to probe the FSB with very expensive gear though.  
This very high frequency interface will make probing and snooping on the bus extremely difficult, which is unfortunate because the Xbox1 security was compromised in part by a FSB bus snoop done by bunnie. At this frequency, the (relatively) simple task of attaching probe wires to the FSB will change the impedance seen on the bus by the FSB PHYs and cause the bus to fail to work correctly (look at eye diagram...). It might still be possible to probe the FSB with very expensive gear though.  
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*http://g-prime.net/x360/open/  
*http://g-prime.net/x360/open/  
*http://www.darkmoon.org/xbox360_photos.htm
*http://www.darkmoon.org/xbox360_photos.htm
[[Category:Xbox360_Hardware]]

Latest revision as of 00:24, 7 January 2014

(This page is riddled with speculation and extrapolation of information from dodgy sources, so take it with a grain of salt.)

The Xbox 360 motherboard (or motherboard) has undergone a few revisions, as Microsoft has corrected mistakes or added/improved existing features.

  • Known revisions include:

Details

The motherboard PCB has four layers (sources: [1], [2]), implying that the top and bottom layers (the ones we can see and probe) contain most of the signals. This is a good thing :)


CPU, GPU, & Front side bus

According to these three sources the FSB is a serial bus with 16 differential pairs in each direction, and each pair runs at 5.4Gbit/s. This agrees with Microsoft's published bandwidth specification of 21.6 Gbyte/sec (10.8 Gbyte/sec each way, 16 bits/2 bytes at a time, 5.4 Gbit/sec per pair).

Looking at photos of the motherboard, we can see 40 pairs of carefully routed tracks between the CPU and GPU. 32 pairs (16 each way) + 8 clock/handshake/parity? pairs = 40 pairs.

This very high frequency interface will make probing and snooping on the bus extremely difficult, which is unfortunate because the Xbox1 security was compromised in part by a FSB bus snoop done by bunnie. At this frequency, the (relatively) simple task of attaching probe wires to the FSB will change the impedance seen on the bus by the FSB PHYs and cause the bus to fail to work correctly (look at eye diagram...). It might still be possible to probe the FSB with very expensive gear though.

It's not very likely that they made the mistake of sending sensitive information on an exposed bus again though.


Photos