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Where can I get white papers for the AMD chipsets?

Last response: in Motherboards
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November 19, 2009 4:49:01 PM

I want to know more abot the SB750 chipset for the AMD. I want to know details such as whether the SATA controller provides 6 real SATA channels with 3Gb/s bandwidth for each channel or of they share the same channels using port multiplicators, the logical layout for the bus etc. i.e. information that is not on wikipedia.

Does anyone know where to get this information?
November 19, 2009 4:58:44 PM

developer.amd.com > developer manuals
November 21, 2009 10:31:51 AM

Thanks, I didn't how to get to AMD's developer community before. I used to think that such information was proprietary and required a paid subscription of something, kind of like MSDN.

I've been flipping the pages of the relevant chipset manuals and when looking at the diagrams it looks like the controllers share a Link A (6 GB/s - I interpret it as Gigabyte per second) bus. The diagram doesn't provide any detailed information about how the SATA controller is designed, only how it is controlled through BIOS and the software layer. So there might be port multiplicators although they are not shown in the diagrams.

There seems to be a misprint because I see only 5 Device IDs for the SATA controller and one Device ID for the PATA controller. In one manual they are 4390h-4394h and in another manual they are sharing the same Device ID as 4380h and the PATA is 438Ch in both manuals.

In real life when looking into BIOS there are 6 ATA/IDE channels and when connecting two PATA devices they will show up on the first two ATA channels, so it looks like the SATA controller shares two channels with the PATA channel. So you can only connect up to 6 ATA devices. If you use all SATA ports the PATA port will be unusable, and then the manuals said something that this could be worked around in the drivers but is not supported by the BIOS.

I could see that there is something called "Combined Mode" where the SATA controller cooperates with the IDE controller so as to provide compatibility with IDE based SATA devices which makes me even more confused.

It seems like you can only use 4 ACHI drives and not 6, the last two devices will be forced to use some native IDE mode. There is no word on JBOD support in the manual although MoBo manufacturers state that MOBos using the SB750 chipset does support JBOD.
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