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TUSB8040A transfer rates

Wayne Pietluck
Prodigy 80 points
Other Parts Discussed in Thread: TUSB8040A, TUSB9261

What might cause a 3.0 device like a flash drive to communicate through the TUSB8040A at high-speed over the 2.0 channel instead of using the super-speed channel?

I verified that the flash drive communicated at an average of 98 MB/s when connected directly to the PC (which exceeds the 60 MB/s max high speed rate), so I'm sure it was using the super-speed channel when connected directly to the PC.  The average transfer rate when connected through the TUSB8040A was only 27 MB/s.

  • 0
    TI__Mastermind 36085 points

    Hello Wayne,

        The USB3's throughput depends on several factors starting from the Host controller, the USB3 driver version, the load and latency of the S.O., the compatibility  between the USB devices, the number of devices connected on the USB3 tree among others. I am sorry for the wide answer but I cannot be more specific with the provided information.

    Best regards,

    Diego.

  • 0 in reply to Diego Cortes
    Prodigy 80 points

    Diego:

    Thanks for your quick response.

    We conducted an experiment with a Seagate FreeAgent GoFlex USB 3.0  1TB Ext HDD flash drive to measure the min, max and average data transfer rate.  When plugged directly into the PC, the average transfer rate was 84.6 MB/s.  When the same flash drive was connected to the same PC port through and external hub from SIIG 3.0 hub, the average transfer rate was 83.8 MB/s.  When the same flash drive was connected to the same PC port though the TUSB8040A in our prototype, the average transfer rate was only 27.4 MB/s.  So while not providing the specifics to all the variables you mentioned, the only variable that changed was the SIIG external hub and the TUSB8040A hub in my prototype.

    We repeated the tests and saw similar performance with a Patriot USB 3.0 64GB XT flash drive.

    The SIIG and TUSB8040A hubs had about the same super-speed data transfer rates (~102 MB/s) when the test was repeated a third time with a Fantom USB 3.0 3TB Ext HDD.

    So all three flash drives had super-speed data rates when connected directly to the PC or through the SIIG external hub; but only one of the three when connected through the TUSB8040A hub on our prototype.

  • 0 in reply to Wayne Pietluck
    TI__Mastermind 36085 points

    Wayne:

        I need to know in which O.S. are You testing the throughput and the following information about the USB3 Host: 

    manufacturer:

    Model:

    Driver version:

    Best regards,

    Diego.

  • 0 in reply to Diego Cortes
    Prodigy 80 points

    Manufacturer and model: AMD USB 3.0 eXtensible Host Controller - 0096 (Microsoft)

    Driver Version: 6.2.9200.16420

    Driver Date: 9/19/2012

  • 0 in reply to Wayne Pietluck
    TI__Mastermind 36085 points

    Hello Wayne,

        We do not have throughput records with the AMD USB3 Host controller, however it seems to be an issue related with compatibility between the devices. A known good setup for throughput setup is using the TUSB73x0 (connected to a PCIe Gen2 port) as Host controller, TUSB8040A and the TUSB9261 with a SSD attached.

    Regards,

    Diego.

  • 0 in reply to Diego Cortes
    Prodigy 80 points

    Back to my original question, do you have any ideas as to what might cause a 3.0 device like a flash drive to communicate at 2.0 high-speed instead of using the super-speed channel?

  • 0 in reply to Wayne Pietluck
    TI__Mastermind 36085 points

    Hello Wayne, 

        the USB3 devices are being enumerated as 2.0 instead of 3.0, or just running at high speed data rates.

    Regards,

    Diego.

  • 0 in reply to Diego Cortes
    TI__Guru 60870 points

    Hi Wayne,

    The USB 3.0 driver is an older one, I would recommend updating it.  That said, our hub should still enumerate well with the older driver.  Using device manager, can you check if there is an entry for "Generic SuperSpeed USB Hub"?  I would like to confirm if the issue is that the hub is not connecting at USB 3.0 speed or if the device behind the hub is not connecting at USB 3.0 speed.

    Thanks!

    Julie

  • 0 in reply to JMMN
    Prodigy 80 points

    One of the three flash drives did appear to connect as a super-speed hub based on the transfer rates.  So I'm assuming that you asking me to check Device Manager for the other two flash drives to see if they connected as high-speed or super-speed, correct?  I'll give it a try.