In , on 02/19/05
   at 05:25 PM, "Ralph Cohen"  said:

>>That's interesting information - the two USB 2.0 cards that I've had 
>>interaction with have both specified transfer speeds for USB 1.1 OHCI as 
>>1.5Mbps,12Mbps and for USB 2.0 EHCI as 480Mbps, but I've yet to see 
>>anything remotely approaching those speeds, using included USB 2.0 cables!

And you won't.  Some of this is marketing.  Some of this is simply not
understanding what the 480Mbps spec applies to.  There are several good
USB tutorials floating around on the web.  The 480Mbps is the bit rate on
the bus.  There's lots of overhead in the data packets and the overall
protocol.  There's also the shared nature of the bus.  These all serve to
make the realistic max throughput much lower.  I would suspect getting 30
MBytes/sec would be considered good, although I have not been able to find
test data to confirm this.

Steven

-- 
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"Steven Levine"   MR2/ICE 2.67
#10183 Warp4.something/14.100c_W4
www.scoug.com irc.fyrelizard.com #scoug (Wed 7pm PST)
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