Using a 6gbps & 3gbps port for a spanned volume with 2 HDDs. Will it affect performance ?

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Plainman

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Theres a HDD connected to the 6gbps port and another connected to the 3gbps port and they are combined to form a spanned volume to show up as one disk and ease of use. Will this downclock or degrade the capability of the 6gbps port ? what performance will the spanned volume see ? Speeds of 6gbps or 3gbps or a shared middle level ?

Regards
 
3,000 mbps (aka 3 gbps) ÷ 8 = 375 MBps. Allow for about 10% overhead and you've got about 337 MBps of transfer speed available to the hard drive on the slower port.

Your hard drive, if it is purely a spinner and not a hybrid drive, can't even come close to saturating a SATA II 3 gbps port, let alone a SATA III 6 gbps port.

TLDR - no there won't be any issues unless you've got a really shitty controller.
 
Separate from the theoretical speeds the ports are capable of, you need to be aware of exactly what ports they are. If they are both off the CPU or PCH, you shouldn't notice much if any difference if they are spinners. If one is off the CPU and the other is hanging off a realtek POS controller which is sharing a 1x link with your Ethernet, sound, game and more then you might notice a difference.
 
Thanks for both of your inputs. So would it be right to assume that in today's consumer PC builds only SSD's and Maybe some Hybrid Drives will benefit from 6Gbps ports.

On a side note many manufacturers of HDDs are touting some of their their disks as 6Gbps as a marketing ploy to amplify something that doesn't even make a difference given that its a spinner and wouldnt even cross the 220mbps threshold in transfers.
 
There are some other changes between sata 2 and 3 besides the double speed. E.g. updates to NCQ. But like the two posters before said, in use you won't notice much of a difference with platter-based HDD's. But the sata 3 support most modern HDD's claim, are with regard to protocol support and not the transfer speed. Unless, like you said yourself, we're talking about SSD or SSHD.
 
The only time you will see a performance difference (in benchmarks) is when the HDD is using the built in cache memory. Most of the time the cache is holding the blocks for the allocation table, which reduce the wear and tear on initial sectors. Unless you have have a hybrid or SSD like Plainman says, for normal use, you won't notice a difference.
 
arestavo said:
3,000 mbps (aka 3 gbps) ÷ 8 = 375 MBps. Allow for about 10% overhead and you've got about 337 MBps of transfer speed available to the hard drive on the slower port.

Your hard drive, if it is purely a spinner and not a hybrid drive, can't even come close to saturating a SATA II 3 gbps port, let alone a SATA III 6 gbps port.

TLDR - no there won't be any issues unless you've got a really shitty controller.
Click to expand...
It's actually 300MB/s, not 375MB/s due to using 10-bit instead of 8-bit conversion. ;)

To the OP, you might notice a small difference in burst reads/writes, but beyond that, no spinning HDD will come anywhere near close to 300MB/s for sequential reads/writes; peak for that on the best HDDs is about 170-190MB/s for a single transfer.
 
I'd be more concerned about a spanned array spanning two different controllers than I would be about any difference in the speed of the controller. That could bottleneck you a lot more than any difference in SATA specification would.

General rule of thumb on anything conjoined - you get the (s)lowest common denominator. But as everyone here as pretty much said - spinners can't saturate SATA2 anyway, so no big deal.
 
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