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Harvey
I notice that you are using a USB Hub that supports 2.0. The last USB
Hub I purchased was a few years ago. In researching USB Hubs at that
time, I found that "supporting 2.0" did not mean that ALL the ports
supported 2.0. Almost all of the Hubs had 1 or 2 ports that were 2.0 and
the rest of the ports were 1.1. I do not know if more recent USB Hubs
support 2.0 on all ports, but I pass this information on in case it
might be of assistance.
Tom
On 1/4/2010 9:48 AM, Andrew J. Rozsa wrote:
> At 08:56 PM 1/3/2010, Harvey wrote:
>> I recently bought a Canon CanoScan 8800F scanner and it supports Hi
>> Speed USB 2.0. I connected it to my computer a AMD GA-M57SLI-S4
>> motherboard. When I turn on the scanner I get the message "This USB
>> device can perform faster if connected to a Hi Speed 2.0 port."
>> How can I tell the speed I'm running at? Since they say that the Hi
>> Speed runs 40x faster then USB 1.1 there would be a major difference
>> in performance.
>> The motherboard manual just says it supports 2.0/1.1. The Hub I'm
>> running it through supports Hi Speed 2.0 and is self powered.
>
> Hi, Harvey
>
> It is my understanding that it all depends what else you have
> connected to the hub. If one single device is running at 1.1 speed,
> ALL the devices connected to the same hub will fall back to 1.1. So,
> although your USB 2.0 is capable of transferring raw data rate at
> 480Mbps, you might be actually down to a 12Mbps (or less). Since I
> have some old (but fully functional devices) I have separate exclusive
> hubs for 1.1 and 2.0.
>
> Also, a USB hub has to re-calculate the time left before the next sof
> (end of the uframe); the small extra delay added by the hardware hub
> could make the transaction not handled as fast as a device directly
> connected to the host. If several devices are connected on the USB hub
> and working in parallel (for example, a webcam + a USB flash drive + a
> mouse), then the USB bandwidth is shared among the devices usage. USB
> hub ports are not as capable or flexible as real PC ports so you can't
> expect top spec performance from them.
>
> When I built my PC I made sure that I had oodles of internal USB and
> FireWire ports (8 and 3), so that I can connect critical external
> devices (like hard-drives) directly to them.
>
> USBInfo & SiSoftware Sandra can report your USB speed status.
>
> Hope this helps.
>
> Andrew
>
>
>
>> HarveyRose
>> [log in to unmask]
>
>
PCBUILD's List Owners:
Bob Wright<[log in to unmask]>
Mark Rode<[log in to unmask]>
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