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Can Intel P45 support FIS-based port multipliers?

Last response: in Storage
August 22, 2009 11:04:09 PM

Hello having read various prerelease announcement on the Internet about P45 (codename: Eaglelake) I was under the impression that it supports FIS-based port multipliers (instead of just command-based). Recently, however, I read regarding the upcoming P55 chipset that among its new features is support for FIS-based PMPs on two SATA ports. Does that mean that P45 never supported FIS based PMPs?

After much searching, the only place where port multiplier support is mentioned on the Intel website is here: and it doesn't mention FIS.

Since FIS-based PMPs is something I will probably be using in the future as my hard drive needs expand, can somebody tell me with certainty whethermy P45 motherboard can support them?
August 23, 2009 12:51:48 PM

The answer is yes. Intel certainly doesn't make it easy to get to the answer, I found that it does by reading the specs of the ICH10R which you can find at

On page 502 you will find the registers that implement FIS based switching. Their presence implies support IMHO.

a b G Storage
September 7, 2009 5:24:54 PM

The datasheet is wrong, the FIS based switching was planned originally, but Intel pulled it quietly. Infos in a linux-ide posting. But now the P55 is supposed to have FIS on two out of 6 ports, eSATA surely...