On Thu, May 05, 2005 at 08:55:48PM +0200, Ulf Soderberg wrote:
BTW, what transfert rate do you get in TX and RX? With what kind of USB bridge?
I get 19 MBytes/s RX and 17MBytes/s TX on a Compaq Evo N800w running Windows XP SP2 at 2.2 GHz. It says it has a NEC PCI to USB EHCI controller. Don't know which chip exactly.
17~19MB/s, not bad, esp. with a NEC bridge, which is told to be limited.
Do you have some overruns/underruns? What is the lowest rate
(decim/interp) without overruns/underruns?
Out of curiosity, how does it compare under Linux with same machine?
I tried the same tests on the same machine using Matt's USRP KNOPPIX Beta and got the following results.
RX => 24.57 MBytes/sec 41 overruns using "test_usrp_standard_rx" 41 overruns using "test_usrp_standard_rx -D 8" 5 overrund using "test_usrp_standard_rx -D 1"
TX => 20 MBytes/sec 32768 underruns (slightly suspicious number, I would say)
So it's definitely faster on Linux. I guess the difference in throughput is directly related to the different overhead added by the device driver architectures in Windows and Linux. (the glue between the hw and libusb)
/Ulf
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