USB 3.0 Review With the ASUS U3S6 Add-In Card

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USB 2.0 has been with us since April of 2000, giving us 10 years of USB goodness and running at 480Mb/s (35MB/s).  You can get almost anything USB now-a-days, including external tape decks and turntables.  Hard to believe there are over 161 million USB devices out there as of March 2009.  Many people have been happy with USB 2.0.  On January 5th, 2010, USB 3.0 was released with an astounding 5Gb/s theoretical throughput! After protocol overhead, 400MB/s  should be easily achieved…that’s over 10 times faster! Lets go over the changes to the new 3.0 spec.

  • Higher transfer rates.
  • Increased maximum bus power to 900 Ma, from 500Ma.
  • Full duplex data transfers (read and write simultaneously)
  • New cables for high speed transfers, however backward compatible with USB 2.0 devices.
  • SUPERSPEED USB has a 5 Gbps signaling rate, offering 10x performance increase over Hi-Speed USB.

The NEC (D720200F1) host controller is the magic to this card, allowing USB 3.0 to achieve 5Gb/s speeds.

Ok, enough with the technical talk, lets see some benchmarks!

Ok, as you already know we are using the ASUS U3S6 4x PCI-e add-in card, along with the Bytecc Super Speed USB 3.0 T-200U3 external docking station.

Contents of ASUS box
Contents of ASUS box
Contents of Box
Contents of Box
150gig WD VelociRaptor Via Bytecc USB 3.0
150gig WD VelociRaptor Via Bytecc USB 3.0
150gig WD VelociRaptor Via SATAII (ICH7)
150gig WD VelociRaptor Via SATAII (ICH7)

As you can  see, USB 3.0 is just as fast has having eSATA device. USB is much more popular than eSATA, and as time goes on, you’ll be seeing more USB 3.0 devices and controllers.  Personally, I’m interested in larger USB flash drives carrying the 3.0 spec.  Since it is now full duplex, we may be able to install on OS onto it, and since its 10 times faster, we may have ourselves an SSD alternative for a Multi-OS system.  With a few 32gig USB 3.0 flash drives laying around, you can have Linux, W7  and or XP right at your finger tips. How cool would that be?

Since the impressive part is out of the way, lets take a closer look at the U3S6 controller.

Close up of the ASUS U3S6 add-in card
Close up of the ASUS U3S6 add-in card

What do you see that this card does NOT have? You are correct, no external power connector! Having a 4x PCIe has its advantages other than more throughput – more power as well! Plus since 1x PCIe has a limit of 250MB/s, having a 4x slot eliminates the bottle neck.  However, having all 4 ports running could have some issues in terms of bandwidth. Which can not be proven at the writing of this review. I do not have SATA 3 SSD’s drives to test.

2 x USB 3.0 ports are blue!
2 x USB 3.0 ports are blue!

As you can see that these ports are backward compatible with USB 2.0 and 1.1.


We can see there is a huge advantage having USB 3.0.  Its essentially eSATA but in USB form.  Having the ability to achieve SATAII speeds via USB is just amazing.  I was extremely impressed with the 150gig Vraptor achieving 122MB/s read! We can now install an OS on an external USB drive, and probably setup RAID as well.  Full duplex is a huge plus for USB3.0.

A few people might not want to lose a 16x graphics slot for this device, since it will kill the chance of ever going SLI or Crossfire,  and some may argue that 1x solution cards are fine for them because they’ll never hit the 250MB/s cap as mechanical drives do not come close to hitting this.   However,  the U3S6 has two SATA 6G ports as well, which probably would not work too well at 1x speeds.   There is a ying and a yang to everything. Pro’s and cons. What do you want?

On the other hand, I love it and will be buying more of them since its not limited to the P55 chipset.  ASUS is stating that it will be only compatible with their motherboards.  This is clearly not the case.  I’ve  tested the U3S6 in the P965 and G31 boards, and both have worked flawlessly.  So if you think you can’t get USB 3.0 on an older system, you’re mistaken! Most likely this is a ploy to try and force you in buying more ASUS products to use the U3S6 device. I love it, however you’ll lose a 16x slot to use it.


About Joe Schibani, Jr. 4 Articles
Director of IT / Network Administrator


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  1. It's still a bit of a gamble as we still don't know if either the sata3 or usb3 works anywhere near their top speeds, but it seems to be the best option out there at the moment.
    It's still a bit of a gamble as we still don't know if either the sata3 or usb3 works anywhere near their top speeds, but it seems to be the best option out there at the moment.

    That's because no one has the dough to dish out for SATA 6 SSD's....
    But as for external USB 3.0, its a home run for that...
    I would love to see an addin card like this for laptops. Perhaps pcmia or pci express. May not be as fast but USB devices are vital for the portable world.
    got this card and a Vantec USB 3.0 hard dock enclosure. Unable to make it work with my Asus P5K-E-Wifi m/b. Need help,thanks

    Is the U3S6 device seen in the device manager?
    Indeed this is a good thing coming. Though SSD SATA III drives aren't that pricey... im mean still expensive but not overly bad price for the fastest of its kind @ $420ish for 128Gigs.
    Looking forward to adding one of these cards to my PC, or better yet getting a motherboard that has it embedded in the future.
    anyone know a usb 3 enclosure that holds multiple drives? I never understood the usb 2 ones cause 1 hard drive saturated usb2 but you could put 4 hd's on each usb3 channel and massivify your storage
    Yes, device manager shows both the Marvell 91xx Sata 6G controller and NEC Host Controller and Root Hub working properly. NEC firmware update from Asus was downloaded and installed. Vantec USB 3.0 hard dock enclosure works in USB 2.0 mode via USB 2.0 cable. I've not tried the Sata 6G connections yet because I'm still waiting for my Sata 6 hard drive to arrive. Is it possible for IRQ inteference? Presently, I also have a PCI-based Promise Sata 3 card installed in one of the PCI slots. Thanks for your response. I really would like to get this thing working.