We have bought a B200 board and are having issues simply receiving the
samples and would like some support in the matter.

Running the command
  ./rx_samples_to_file --null --rate 56000000
on a Sony Vaio Z with an I5-3210M running Ubuntu Server 17.10 shows a
high CPU usage of ~78%.

Is such a high CPU usage expected?
Switching terminal windows (ALT + F1 or ALT + F2) is enough to cause an
overflow on the Linux host.

There is also a high CPU usage on a Windows 10 machine (ThinkPad,
  ./rx_samples_to_file --null --rate 56000000
results in a infinite stream of overflows.

  ./rx_samples_to_file --null --rate 32000000
utilizes 22% CPU and still overflows once in a while. Moving a
calculator window around the screen results in overflows.

We have tried increasing buffers using --args="recv_frame_size=X,
However, we haven't been able to increase X to higher values than ~16000
(16384 fails with lots of overflows).
The same applies to Y, where 300 fails with an error.

The software was compiled in release mode an ran over a USB 3 connection.

Thus, for USB transfers using the B200:
 - On Vaio: Is ~78% CPU usage expected for 56 Msps ?
 - On Win10: Is it not possible to receive 56 Msps?
 - On Win10: Is 22% CPU usage expected for 32 Msps?
 - Is there some limit to recv_frame_size? A value of 16384 fails with
infinite overflows.
 - Is there some way of tuning the framework for lower CPU?

We hope you are able to help!

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