@n5fpp I have no idea what is normal when you are processing 56 million samples per second. My crappy computers usually wont allow me to go above 10-20 Msps 
There is only one gqrx process but gqrx is massively multi-threaded so it will use all the cores you can throw at it.
Note that the 100 MHz bandwidth can be 60 and only for HF below 30 MHz. Above 30 Mhz you can set it 0.
USB3 and drivers seems to be a bit of an issue. They are with Ettus too. I am still trying to get this to work on my high spec PC with Simonās SDR Console, where it runs for a few seconds and freezes. It works OK on my laptop though, I can listen to Radio 4.
Has anyone figured out what current the board takes from the USB3 ports as I am wondering if this is the problem - though I have tried using a 2A USB supply on the pig tail without success. I have not yet tried using the DC connector.
Meanwhile I have ordered some USB3 extender cables as the supplied cable was just about but not quite long enough to be useful.
Mike
If it works a few second and freeze , check your USB port , maybe not enough power supply
Just took a measurement with an dongle that claims to support USB3, but maxes out at 10 MHz stable bandwidth. At 10 MHz it returns about 2,56 W. At 20 MHz it reads 3,22 W right before SDRConsole freezes.
Im am using a front port, will try one directly fed from the mobo.
with me , It stable at 60MHz but you must using its short usb cable and plug dirrectly to USB3 port on MAINBOARD. My CPU i7 mainboard ASUS . Using USB3 port at front only work a few seconds
Seems like my problem on one PC was the software had become damaged or modified. A complete re-install of the Pothos SDR development environment made it work.
It could be the USB power. I am using the front ports as the supplied cable is so short thatās all I can use and it seems happy enough, but I am using two portsā¦ I am going to check the current required with a DC supply once I work out the voltage specification needed, but this appears a very power hungry device so it might not be sensible to try to power from USB.
RF performance is pretty dire - as expected - due to the DC-daylight front end. Definitely needs a filter. A filter bank would make a good project.
Update - external power is stated as 6-12V. Set for 10MHz bandwidth, 6V 880mA, 7V, 720mA,8V, 620mA, 9V 550mA 10V 500mW or to put it another way, about 5W consumption. No wonder the USB isnāt happy. I also found it crashed when changing the voltage so be aware. Increasing the sample rate raised the requirement to 6W, Reducing it to 2.5MHz didnāt make much difference, still 5W.
This is with just one receiver active.
The chips are hot, (see other thread). The FBD test (finger burn duration, how long can you stand it for - about 5 seconds) indicates about 60C.
Mike
Hello
I have one by one head usb3 cable and i want to know that if i use two channel receiver (RX1-L and RX2-L) then how much essential to use one by Two heads USB3 cable?
Best Regard