# help me understand the difference in sata controllers



## fullinfusion (Aug 11, 2012)

My mobo has 2 seperate 6GB sata connectors. 

One controller is an Intel Z68 sata 6.0 GB's connector.

The second controller is a Marvell sata 6 GB's connector.

Is there any difference? Is one better then the other?


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## lilhasselhoffer (Aug 11, 2012)

The difference is that one of the controllers is integrated into the PCH, and the other is an add-on chip.

Intel only integrated a limited amount of SATA ports into the PCH.  In order to add more ports a manufacturer takes up PCI-e lanes, and adds an expansion chip to convert SATA traffic into something that can travel along the PCI-e bus.

Practically, the difference is two fold.  Intel integrates RAID into most of its chipsets.  If you want to RAID a pair of drives they need to be using the same chip.  Additionally, most Marvell chips don't support RAID.

So, if you want to RAID, keep the Intel PCH ones free.  If you just want a large number of discs, then populate whatever slot you'd like.



On a personal note, Marvell SATA controllers have flaked out on me in the past.  Just make sure to backup any important data, as it can be worth while if you never need it.


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## fullinfusion (Aug 11, 2012)

So Im not using raid.... I have a Vertex 4 128GB ssd and a 1TB western Digital Black 6GB spin drive... I have both plugged into the Intel sata port... What i need to know is the other Marvell port going to be faster? or are both Intel and Marvell ports running at 6GB's the same speed wise?


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## lilhasselhoffer (Aug 11, 2012)

Yes, they both ideally run at the same speed.  Again, it is rarely substantiated but I believe the Marvell controllers run slightly slower than the Intel ones, not really enough to notice though


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## Mussels (Aug 11, 2012)

secondary controllers (the marvell in this case) always suck for performance, since they're connected by 1x PCI-E links most of the time.


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## Mindweaver (Aug 11, 2012)

Yea, I only use the secondary controller for backup drives and storage drives, because they are slower.


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## Aquinus (Aug 11, 2012)

Mussels said:


> secondary controllers (the marvell in this case) always suck for performance, since they're connected by 1x PCI-E links most of the time.



It's not just that, but a lot of additional SATA controllers in addition to the ones provided to the PCH run slower, not because it's using PCI-E 1x but because that PCI-E lane goes into the PCH, so it has an entirely extra bus to go through. So instead of going from the PCH to the CPU via DMI, it has to go through PCI-E, through the PCH and then through DMI. So your limited by the bandwidth on PCI-E 1x and by any load that might already be on the PCH.

For example, if you're connected to the network with gigabit and your copying data to a drive on a secondary SATA controller, you have the Gigabit LAN using DMI to receive that data to send it to the processor and system memory and DMI again to write the data to the disk plus any overhead introduced by the PCH's PCI-E lanes.

But honestly, the real limitation is the PCI-E 1x @ 2.0, because your limited to 5GT/s which is 500MB/s excluding PCI-E protocol overhead. So you will never see full SATA 6G speeds on it. However for rotational media drives, it should work fine. I would keep the SSDs on the PCH though since it can handle two SATA 6G ports at full speed and not just one at gimped speeds.


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