Information on Mac Pro 4,1 SATA controller please

funkahdafi said:

Hi,

I know it has some Intel based SATA controller, and it does have 6 connections (4 bays and 2 optical bays). What I am wondering is if this is just one controller (so all 6 connections share the available bandwidth) or whether it actually has more than one controllers, and if so, which bays are connected to the same.

The reason I am asking is I want to find out if there could be any benefits of placing hard drives into specific bays when putting them in a RAID0 array. Spreading the drives across multiple controllers...

Anyone know?

Thanks

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I have a 2008 Mac Pro 3,1 and from what I can see (MacPro Developer Notes) there are 6 SATA-II 3G channels originating from the SouthBridge chip. I run both SSDs and hard disks in software RAID-0 and there is a significant increase in performance in doing so. I don't think it will matter which bays you use for the array drives.

If you want absolute maximum speed, check out the thread on here about the Solo x2 SATA-III PCIe card, and running a pair of them in RAID-0. Or check the more expensive OWC "Accelsior" PCIe RAID-0 SSD drives available in several different sizes.


-howard

funkahdafi said:

Thanks. Yes, I know about the Solo x2 (using one myself). I was wondering about the internal controller though.

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I think the internal SB chip may have 6 independent SATA-II controllers rather than some kind of bridging, since I see a noticeable speed improvement when running high speed SSD drives in RAID-0 versus single SSD drives in the standard drive bays. If these SATA-III SSD drives were approaching the saturation point of the SATA-II bus controller, I wouldn't expect a speed improvement when I presented additional parallel data to that controller, unless there were parallel processing controllers.

I have put the same drive(s) on the Solo x2 and get additional speed from a single drive via the SATA-III interface. I had read that running the x2 with 2 drives in RAID-0 would saturate the board bus, and the solution was to use 2 PCI cards, which I can't do in a 2008 Mac Pro due to the available bus arrangement.

The OWC "Accelsior" gets its speed from having 2 SATA controllers on the card for RAID-0.


-howard