To USB or Not to USB

PC Chipsets with integrated USB 3.0 (from the Innovator/inventor of USB) started shipping at the beginning of April for reviews.

Here’s a table from Anandtech clearly showing there will be 4 USB 3.0 ports!

They’ve added 4 USB 3.0 ports and to the existing 14 USB 2.0 ports.

If you look at your laptop or desktop, you won’t see that many USB 2.0 ports on the outside because some are used internally.  They connect to a 3G modem or a card reader or ExpressCard slot.

ASUS, HP, Samsung, Toshiba, and others have already announced they will have laptops based on the Ivy Bridge chipset, just Google Ivy Bridge PC and you’ll get all the models

It turns out that AMD has been shipping a motherboard also.

I found this article comparing the performance of the Ivy Bridge and AMD integrated chipsets against NEC, VIA, and ASMedia USB 3.0 Host controllers at http://techreport.com/discussions.x/22775.

Here’s part of the Graphs from that Report.

  From http://techreport.com/discussions.x/22775

As expected, the Ivy Bridge Chipset performs faster, it’s the Blue bar.

I’m going to make you go to the actual article at techreport.com to see what the other chips and integrated chips sets are on the graph because I think the website deserve the hits.

Integrated is Faster

Ivy Bridge is faster because it’s fully integrated:

The stand alone chips used in the NEC, VIA, and ASMedia Hosts can NOT achieve faster speeds because they are limited by their PCIe Gen 1 x1 connection to the motherboard.   PCIe Gen 1 x1 can only go up to 2.5 Gbps, and it’s less in a system where many PCIe peripherals are using the PCIe bus.  Ivy Bridge shouldn’t suffer from this because it is fully integrated into Ivy Bridge and probably has at least a PCIe Gen 1 x2, x4, or even x16 to make sure there is plenty of bandwidth to move the USB 3.0 data in and out of the system. 

For detail on factors that reduce or increase USB 3.0 performance read this blog entry.

I’m going to make you go to the actual article at techreport.com to see what the other chips and integrated chips sets are on the graph because I think the website deserve the hits.

Why the performance isn’t even faster (maybe)

Performance Note: the report does NOT tell us what kind of USB 3.0 Drive they used for testing. I can actually guess which Flash Drive they are using based on the max read speeds that I see, but that will be for a later blog entry.

I think the throughput is limited by the speed of the actual USB 3.0 Hard Drive or USB 3.0 Flash drive being used.

1. If it’s a USB 3.0 Hard Drive, it probably uses a bridge chip from USB 3.0 to a SATA 3 Gigabit/second (Gb/s). This means the maximum Read speed would be near 300 MegaBytes per second (MB/s) or about 3 Gb/s. 
2. If it’s a USB 3.0 Flash Drive, it’s speed will be limited by the quality of the Flash inside the drive.  The fastest flash speeds we’ve ever seen is about 300 Mb/s with a $600 SuperTalent flash drive that arranged 2 banks of flash in a RAID configuration.   At $600, this isn’t a really a consumer product.

   Basically, it was fast because it used the fastest Flash memory, lot of it (128GB), and arranged it in two pieces for simultaneous access to both pieces.  I don’t consider this to be a commercial product, and it didn’t sell that many because it cost more than a Hard Drive, but it gives us an idea of what performance is possible with Flash Memory.

USB 3.0 in Tablets

Apparently Ivy Bridge is also targeted at Tablet PCs with Win 8.   This makes Ivy Bridge the second chipset with integrated support along with TI’s OMAP 5 demonstrated at CES 2012 in January.

This confirms Rahman Ismail’s comments (USB-IF CTO) correctly stated USB 3.0 in tablets and smart phones will be appearing in 2012.

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> From: Name Withheld
> Sent: Thursday, April 19, 2012 5:35 PM
> To: Eric Huang

> Subject: Love your blooper on youtube!

> I just KNEW you were human!

My response:
> Was I a nematode before?

His Response:
> Correct

(Nematode = Worm)

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