First SATA 6Gbps chipset is likely bottlenecked

Author: Richard Swinburne
Published: 4th June 2009
Comments (12) Stumble
First SATA 6Gbps chipset is likely bottlenecked

EVGA claims it will continue to test the Silicon Image SATA 6Gbps chipset to check if there is bandwidth issues and whether using it is really worthwhile. Gigabyte and Asus will feature it at launch.

COMPUTEX 09: In discussion with EVGA this afternoon we asked why, considering the company is a leader in the latest fastest technologies, the company wasn’t combining the latest X58 and P55 motherboards with SATA 6Gbps.

EVGA replied it had looked into the first generation Silicon Image chipset but reckons that since it’ll be only connected via a PCI-Express x1 interface, it’ll likely be bottlenecked.

Not only that, but the SATA 6Gbps specification was only recently finalised, so there will be no products to take advantage of it for a while yet and the benefit versus cost to end user is limited for now.

With only Silicon Image launching a SATA 6Gbps chipset for now – and we’ve not heard any other chipset in the works yet – it’s likely to be somewhat expensive.

With only SSDs realistically pushing the limits of the SATA 3Gbps specification, but no SSDs yet committed to the 6Gbps spec, we can certainly see EVGA’s reasoning - especially if the claim of a performance bottleneck is true.

We’ll be sure to test it when the boards and hard drives are available. Until then, discuss it in the forums.
Quote Skiddywinks 4th June 2009, 13:52
Hmm, interesting opinion. Some benchmark numbers would be nice.
Quote TomH 4th June 2009, 13:57
"...especially if the claim of a performance bottleneck is true."

Well, it's not hard to work out: a single PCI-E 2.0 lane can carry only 500MiB/sec in either direction. 6Gbps is 750MiB/sec. Even if it doesn't theoretically reach that, it's still likely to be higher than the single PCI-E 2.0 lane can carry.

Fair play to them, in all honesty. It would only serve to drive the price up, and if you can really afford an SSD that can challenge the rate of 3Gbit SATA, then you shouldn't have an issue purchasing a 6Gbit SATA controller, that sits in a 2x/4x interface. :)
Quote Paradigm Shifter 4th June 2009, 14:01
I'll only really care about SATA 6Gbps (why not call it SATA3? Or does that run too much risk of confusion with SATA2/SATA 3Gbps?) when drives start to saturate the SATA2 bandwidth available. And currently the only things getting even close to that on sustained transfers are ludicrously expensive RAID SSD setups.
Quote oasked 4th June 2009, 14:26
Not going to be a problem for a while, seeing as the majority of drives don't even get close to SATA II speeds anyway. The limit isn't with the connection, its with the drives themselves.

If I could afford a large SSD that would max out my SATA II connections, that'd be great - but I know it won't happen for a few years. :)
Quote Skiddywinks 4th June 2009, 14:45
Quote:
Originally Posted by Paradigm Shifter
I'll only really care about SATA 6Gbps (why not call it SATA3? Or does that run too much risk of confusion with SATA2/SATA 3Gbps?) when drives start to saturate the SATA2 bandwidth available.

That's exactly why. SATA2 and SATA3 are incorrect names that people just made up to coincide with the release version, and such a naming scheme is exactly what SATA-IO didn't want. Officially, they are called SATA 1.5, SATA 3 and SATA 6 so that there is no confusion when it comes to transfer speeds.

SATA II Misnomer
Quote Paradigm Shifter 4th June 2009, 15:56
Quote:
Originally Posted by Skiddywinks
That's exactly why. SATA2 and SATA3 are incorrect names that people just made up to coincide with the release version, and such a naming scheme is exactly what SATA-IO didn't want. Officially, they are called SATA 1.5, SATA 3 and SATA 6 so that there is no confusion when it comes to transfer speeds.

SATA II Misnomer
Ah, the wonders of the internet - once someone has coined something, if it becomes popular it doesn't matter if it's technically inaccurate! :)

Of course, the motherboard manufacturers are seriously to blame for that, then - my SATA 3Gbps ports are all labelled 'SATAII' or 'SATA2'. ;)
Quote Pookeyhead 4th June 2009, 16:08
Well.. my fastest drive doesnt even get close to saturating the current SATA, and seeing as this will not really see the light of day until it makes economic sense on a mainstream board, I'm not bothered right now.

Just a shame that X58 will no longer be a mainstream/enthusiast board by then.. thanks Intel :(
Quote Chocobollz 4th June 2009, 16:55
Quote:
Originally Posted by TomH
Well, it's not hard to work out: a single PCI-E 2.0 lane can carry only 500MiB/sec in either direction. 6Gbps is 750MiB/sec. Even if it doesn't theoretically reach that, it's still likely to be higher than the single PCI-E 2.0 lane can carry.

I'd say 6 Gibibit/s is their *maximum* theoritical bandwidth, and so that doesn't imply that they will use all of those bandwidth. How fast are the current fastest SSD throughput? 250 Mebibyte/s? If so, that single-lane would be sufficient (at least for now).
Quote iwod 4th June 2009, 17:19
Interesting that an HDD interface is faster then PCI Express Single Lane. Where is PCI Express 3.0 anyway?
Quote Turbotab 4th June 2009, 18:22
No need to stress, PCI-E 3.0 and SATA 6.0 are ready when they are needed, until then why bump up motherboard prices in such tight market conditions.
Quote leexgx 4th June 2009, 20:19
PCI-e 1x is 256MB/s each way (total 512M/s bandwidth but 256MB/s each way only), so Sata 600 most likely does around 550MB/s, they need to use PCI-e 2x or 4x Link or higher

made the above before finding the link below

http://en.wikipedia.org/wiki/PCI-e

even in full duplex its 512MB/s (256MB/s each way), so its not any faster then SATA 300 bit slower in fact (why you norm find that raid cards are norm 2x or 4x PCI-e cards)

Edit
Ops i forgot about PCI-e 2.0 spec it is double the PCI-e 1.0 spec (still need to be PCI-e 2x or 4x thought if its connected via 2.0 spec, as one SSD drive could max it out next year)
Quote TomH 5th June 2009, 10:47
Quote:
Originally Posted by oasked
Not going to be a problem for a while, seeing as the majority of drives don't even get close to SATA II speeds anyway. The limit isn't with the connection, its with the drives themselves.

If I could afford a large SSD that would max out my SATA II connections, that'd be great - but I know it won't happen for a few years. :)
There are such things as port multipliers for SATA, which, when released for SATA 6Gbps, would allow for more than a few SATA 3Gbps drives to utilise a single connection. This is done far more often with SAS drives, but with all that extra bandwidth per lane, it's increasingly likely that manufacturers will begin utilising SATA multipliers too.
Quote:
Originally Posted by Chocobollz
I'd say 6 Gibibit/s is their *maximum* theoritical bandwidth, and so that doesn't imply that they will use all of those bandwidth. How fast are the current fastest SSD throughput? 250 Mebibyte/s? If so, that single-lane would be sufficient (at least for now).
Yes, but what happens when that changes? When there's an SSD that can muster 500MiB/sec? OCZ have recently announced a 3.5" SATA drive, that contains two of their Vertex drives and a RAID0 controller. It won't be long before they are requiring more than a single PCI-E 2.0 lane can carry, and whichever motherboard manufacturer that glazes over this fact is going to have severe amounts of egg on their face (and a tarnished reputation amongst the enthusiast crowd).
Quote:
Originally Posted by leexgx
PCI-e 1x is 256MB/s each way...

..Ops i forgot about PCI-e 2.0 spec it is double the PCI-e 1.0 spec (still need to be PCI-e 2x or 4x thought if its connected via 2.0 spec, as one SSD drive could max it out next year)
This is already in the 2nd reply, towards the top of the thread. Why did you just repeat it?
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