Bottlenecks And Solutions For USB 3.0 And SATA 6Gb/s
All AMD 700 and 800 chipsets (both northbridge and southbridge) fully support PCI Express 2.0, while Intel’s PCIe 2.0 support is limited to the northbridge/processor-based interface (the company continues claiming PCIe 2.0 support on platforms like P55, despite the 2.5 Gb/s limitation). This is why it's unlikely you'll encounter bandwidth bottlenecks on AMD platforms.
But let's say you're looking for a new P55-based motherboard, though. There are still a few options to pursue. Intel controllers typically utilize a single PCI Express lane for the sake of simplicity. Of course, performance bottlenecks could be solved by connecting to the host system using two or four lanes, but that's not the solution you'd want to rely on, since most consumer motherboards only offer x1 and x16 slots.
The first solution is simply to use existing PCIe 1.1 lanes to attach USB 3.0 and SATA 3.0 controllers. This yields a maximum bandwidth of 250 MB/s. Obviously, this approach should be avoided because it handicaps third-generation SATA below the performance levels of even SATA 3Gb/s. It also bottleneck's USB 3.0, too. For individual USB 3.0 drives, this might not be painfully apparent, but as soon as you operate two drives in parallel (or once SSDs exceed 300 MB/s throughput), this bottleneck will start to hurt a lot more.
If you want to see this challenge overcome properly, check out Asus' P7P55D Premium motherboard, which employs a PLX 8613 chip to condense the bandwidth of multiple PCIe 1.1 lanes into a PCIe 2.0 link. Latency-wise, this is not perfect, but it's still better than multiple PCIe 1.1. links. Unfortunately, it's also expensive, resulting in a board that costs more than many mainstream customers are willing to pay. At under $200, the P7P55D-E Pro is perhaps a more attractive mainstream offering that "does switching right."
The second approach to overcoming bandwidth limits is to link high-speed components, such as USB 3.0 or SATA 6Gb/s controllers, to the primary PCI Express 2.0 lanes. This will result in the 16 main graphics lanes sharing bandwidth with high-speed storage interfaces. Gigabyte’s P55A-UD6 uses this solution. Unfortunately, if you actually use the USB and SATA controllers, this knocks your graphics card down to x8 mode. Worse, if you run in CrossFire mode (employing two x8 links), the USB and SATA controller get knocked back to 2.5 Gb/s links. Either way, you're sacrificing performance in order to add support for the latest standards.
Finally, you can allocate available bandwidth in a more flexible way. This is done on Gigabyte’s P55A-UD7 motherboard, which works around the -UD6's limitations. The -UD7 includes an nForce 200 bridge, capable of multiplexing the processor's PCI Express connectivity to support a broader array of graphics configurations (not to mention adding SLI support). A PLX PEX 8608 switch is needed to enable the next-gen SATA and USB controllers found on-board, too.
MSI and Gigabyte use the PLX 8608 PCI Express switch to allow dynamic bandwidth switching between available 16 PCI Express 2.0 lanes, multiple x16 slots, and high-speed devices, including USB 3.0 and SATA 6Gb/s controllers.
Related Stories :
- X58 In 2010: Four LGA 1366 Boards With USB 3.0 And SATA 6Gb/s
- USB 3.0, SATA 6Gb/s, Motherboards, And Overcoming Bottlenecks
- USB 3.0-to-SATA Adapter Gives HDDs SuperSpeed
- ECS Also Providing USB 3.0 and SATA 6Gb/s Cards
- HighPoint to Release PCI-E 2.0 SATA 6Gb RAID
- WD Ships My Passport Ultra USB 3.0 External Drives
- Sitecom Releases Gbit Ethernet Adapter With USB 3.0
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Unfortunately, Intel is a pain-in-the-a$$ for not picking USB3.0 into their mainstream chip until today.
AMD sure know what they can give consumers first hand on technology that doesn't need to cost as much as Intel motherboard.
Bah... enough of 1156...Its been how many months and still too few X58 USB3.0 boards out there.... what more boards that actually utilize the full 6gb/s.
Its hard to be as patient waiting for the right technology and at the right time to upgrade...
why no AMD based motherboards?
why? many of intel motherbaords are limited to pcie 1.1 speed
why no AMD based motherboards?why? many of intel motherbaords are limited to pcie 1.1 speed
It seems that many of Mr. Schmid and Mr. Roos articles are Intel articles. Not a complaint but just an observation.
Why no AMD boards? It's right there; because current AMD chipsets don't have bandwidth problems:
and:
AMD's best CPUs aren't as fast as Intel's, but if you're just gaming, you probably won't see a difference. The AMD platform, however, is superior unless you're willing to pay for X58.
Even though there is no bottleneck on the AMD platform it would have been ok to post result when it comes to the actual speed difference between these 3 boards and one AMD equipped on .. to see how large is this bottleneck in numbers.
Just my 2 cents on the matter
It puzzles me why no one noticed that when utilizing a single AMD 5850 GPU, the Gigabyte UD6 board actually has the fastest throughput!
I'm actually pretty satisfied with a single 5850 GPU card, which is darn fast and good enough for all the latest games), so buying a Gigabyte UD6 board seems the best choice among the 3 reviewed in this article.
Someone correct me if I'm wrong.
Very informative article. It cleared up some misunderstandings about USB and SATA.
I must be missing something. Even with the switching and PLX device, isn't the bandwidth through the PCIe interface more bottlenecked than the SATA 2.0 interface that is natively supported by the 1156 platform? It would be interesting to see a comparison between the tests done here and the performance of the same drive connected through natively supported SATA 2.0 on the same system.
Can we quit with the AMD fanboy whining already? We dont need to see AMD comparisons in this article but it was very clearly stated MULTIPLE TIMES by the author that there is no bottleneck/performance limitation with AMD platorms. I believe the title of the article is "USB 3.0, SATA 6Gb/s, Motherboards, And Overcoming Bottlenecks" which would indicate that it is covering platforms that have a "Bottleneck" and how to overcome it. So if there is no bottleneck for AMD we dont need to have a review of their parts!!!!
BTW thank you very much for posting this article I am currently building a Media Server/NAS and was tinkering with both AMD and Intel builds. This just pretty much slammed the door on any intel build.
First, we need the interface to be twice as fast as PCI-e 2.0 for RAID purposes.
Second, we need to have HDDs and SSDs that perform above the SATA 2.0 mark (375 MB/s Max Throughput).
I can wait for the next generation of chipsets (which will possibily have the PCI-E 3.0).
I am a AMD fanboy and have used only AMD cpu's for 10 years and when i built computers for friends i only use AMD! So it seams that infell is not as good as they say.
This is why I bought 1366 over 1156!
The LGA1156 technology was dead when it arrived. The only thing it has is the removal of the northbridge. I won't and would never buy the 1156-series. It was retarded that they just didn't make them all LGA1366. But that is marketing for ya.
I am not an AMD fanboy and have never used an AMD processor, but I too have to agree with SpadeM and others that there should have been an AMD board thrown in the mix for comparison. Yes the article is "USB 3.0, SATA 6Gb/s, Motherboards, And Overcoming Bottlenecks", and that is EXACTLY why it should have compared these various "solutions" with a bottleneck free AMD set-up. Just how do the suggested solutions compare with a bottleneck free MB??? Are they adequate and cost effective solutions in comparison?
That is the real question that needs to be answered because when I go to buy my next set-up, I would like to know if it's worth sticking with Intel P55, or upgrading to Intel X58, or switching to AMD. A true comparison covering this is in order.
Totally agree with niknikktm +1
This makes for an interesting tradeoff if someone doing a build now. There not a lot of USB/SATA 3.0 peripherals out there yet. The Intel CPUs are plainly better, but they have this IO bottleneck that will be a future issue.
Are the next gen AMD CPU's (Bulldozer, Et Al) going to be backwardly compatible with the current gen Mobos (meaning with the use AM3.) I could see buying a current gen AMD CPU/Mobo, if I can just swap out the CPU later when they catch up to Intel. But if I have to swap out the mobo also, what am I gaining now, when I can't really buy anything to plug into the higher speed ports?
Unless they use raid 0 ssd's a amd vs intel comparison isn't in order.Because a single drive would show no difference,it only shows up on some of the intel boards when you run 2 video cards.......as they have clearly shown in the article.