SDRplay Community Forum

I am using HDSDR on a WIN 7 computer.
at times the waterfall stops scrolling up, and the audio stutters.

It sounds like "Max Headroom".
Y-Y-Y-e-e-e-s-s-s ugh ugh ugh

When this happens the CPU bar at the bottom of the screen says something like:

CPU HDSDR 63%
CPU TOTAL 100%

and the CPU TOTAL bar is RED.

The stuttering only happens when the CPU TOTAL is 100% with a red bar.

The waterfall display only resumes when the CPU TOTAL is less than 100%.

The time period that the waterfall was not scrolling just shows random vertical lines, no real data.

How do I resolve this problem so that the audio is uninterrupted and the waterfall scrolling continues?

I had the same problem with Win 7 x32
I bought a new computer with Win 7 x64 and now my CPU usage is about 7%
It appears that a 2 core version of windows cannot compare with the 4 core one.

Ai8o wrote:I am using HDSDR on a WIN 7 computer.
at times the waterfall stops scrolling up, and the audio stutters.

It sounds like "Max Headroom".
Y-Y-Y-e-e-e-s-s-s ugh ugh ugh

When this happens the CPU bar at the bottom of the screen says something like:

CPU HDSDR 63%
CPU TOTAL 100%

and the CPU TOTAL bar is RED.

<snip>

How do I resolve this problem so that the audio is uninterrupted and the waterfall scrolling continues?

What bandwidth are you trying to receive?

I have been able to use my SDRplay and HDSDR on the inexpensive Windows 10 (32-bit) tablets with 1 GB or 2 GB RAM and the small Intel Atom quad-core CPUs. With these small devices, I can't even dream of using the SDRplay to receive up to 8 MHz bandwidth at one time. I can usually get to the 1.544 MHz range without hearing the stuttering. To me, this appears to be a case of the computer can't keep up with the data coming in on the USB cable from the SDRplay.

On a Windows 7 laptop with more memory and a bigger CPU, I can use the same SDRplay with HDSDR and have no issues receiving up to the maximum 8 MHz bandwidth. I don't need to really use 8 MHz bandwidth when I use my SDRplay as a downlink receiver when working amateur satellites. In fact, I usually keep the bandwidth down to 200 kHz in most cases. Otherwise, when I use HDSDR to write an RF recording of the satellite transponder, those recordings would be huge for only a few minutes of data. I still end up with 400 to 600 MB for a satellite pass of 15 to 20 minutes, which is better than only starting the discussion with a recording that is a couple of GB. Then another pair of limitations comes into play - small size of tablet's C: drive (16 or 32 GB, in my case), and very slow transfer rate when using a micro-SD card as the tablet's D: (or some other letter) drive for HDSDR to write those RF recordings. The laptop has no problems with that, as long as I don't exceed the free space on the drive where HDSDR is writing those recordings.

Good luck, and 73!

Ai8o, as W9ZO says, the obvious answer is more horsepower. What version of W7 are you running and what bit-ness (32/64)? Have you tried any other SDR SWs? I would suggest SDR-Radio especially if you have an nVidia video card. SDR-Radio uses CUDA code in the video card if it is nVidia. This can significantly lighten the load on the CPU. Trial version V3 claims less CPU usage and seems to work fine. If you have a 64 processor, please use the 64 bit version of SDR-Radio. Another obvious question is where is the other 37% (100% - 63%) on your CPU going? I suggest using the Windows Task Manager and Resource Monitor (task Manager-Performance tab-Resource Monitor... button at bottom) to determine this. Reducing the input bandwidth may help reduce CPU load.
Please let us know what you learn and perhaps we can go from there.
Enjoy, John.

Reducing the bandwidth/sample rate will help with CPU load. Our new API will also be more efficient so that should help you as well.

The new API will be released soon, still working on that with the EXTIO update.

Best regards,

SDRplay Support