It's all about the Software

I'm running the latest SDR Console release on Windows 10 21H1 Home (my system has never offered to update past that version for some unknown reason). Hardware is a Core i5-3570K at default clocks, EVGA GTX 960 at default settings and latest firmware. Radio is SDRplay RSPduo with API 3.11.

One thing I like to do is decode WEFAX transmissions. The software I use is the paid version of SeaTTY, fed with the free version of VB-Audio Cables. This used to work fine for me with the aforementioned hardware and software. It still works fine using SDRplay's SDRuno software to run the radio. But one day, it started misbehaving badly with SDR Console. The image decoding loses line synchronization very frequently, sometimes as often as every 30 seconds or so. (This is an approximation, there's no exact timing to it. Sometimes it will go for a few minutes between slips, but once I couldn't even make it through a quick SSTV decode without losing sync.) This is even without any other heavy activity on the system, or even touching the mouse or keyboard!

The only thing I changed between the working and non-working times was that I switched from a 1080-line monitor to a 1440-line monitor. Out of curiosity, I turned off the CUDA processing in Console. Image decoding is much more stable. Not perfect, mind you -- it'll still slip once every other image or so, maybe a period of 10-15 minutes. (Again, this doesn't happen with SDRuno.) I also tried leaving CUDA enabled and switching my monitor's refresh rate from 75 Hz down to 60 Hz (I had boosted it to 75 because this moves some RFI off of some of my favorite frequencies) and again it greatly reduced but did not eliminate the glitches.

CPU usage with CUDA enabled is only 10-15%, and GPU usage is similar, so I'm at a loss as to where the problem is coming from.

Since posting the first message, I've replaced my i5-3570K with an i7-12700F. Sometime prior to that, Windows finally decided to update itself to 22H2.

Not only are the glitches still present, they're now as bad without CUDA as with it! (As before, using any other SDR software is flawless.)

I'm wondering if this isn't somehow a problem with Windows rather than Console -- but still, why is it only affecting Console?

Show pictures of your settings. And is WiFi anywhere in your connection picture? Of so getting it to work will be an adventure if it can be done. Look through the options for the audio latency setting in SDRC. Playing with that might help. The full size unedited picture of your main window for SDRC will be important to show a lot of basic settings information.

Then bring out your "Trouble Shooting 101" text book and start following the generic steps. Bisect the problem down to something that works. Then look in the part you trimmed out to find what is not working for you. Audio sample rates may be an issue if it all works without the audio lash-up through virtual stuff.

Basically, we cannot see what you have there. So we cannot help you except with random suggestions.

{^_^}

After much experimentation, I've come to the conclusion that the blame doesn't lie entirely with SDR Console.

I could get no combination of the audio latency settings to produce anything resembling acceptable output. Glitches were always large and frequent.

Then I decided to try skipping the VB-Cable connection, since my new motherboard's audio drivers, unlike my old one's, provide the "Stereo Mix" device as an input option. (This is not ideal, as it would allow other system sounds to get mixed in with the radio, as well as not allow me to mute the radio if I wished to decode something while listening to other audio, but at least it would provide another debugging data point.)

This time, with the default audio latency settings, things were much better. I would only get one or two glitches per chart, and they only resulted in a shift of a few pixels. Still, trying other settings didn't improve the issue, and often made it worse.

Finally, I belatedly realized that I could try Console with my Airspy radio. This time, decoding is perfect!

So, the problem must lie, in part, somewhere with the SDRplay driver. I say "in part" because the same driver works perfectly with SDRplay's own software. (But I much prefer Console for aesthetic reasons, not to mention inter-device compatibility.)

Next step is to revert to a previous version of the SDRplay driver. Results pending on whether there are any WEFAX transmissions receivable from my location at the moment.

Reverted from 3.11 to 3.09, the oldest version available on SDRplay's website.

Decodes with "Stereo Mix" work fine. Decodes with VB-Cable are horrible.

I'm out of ideas.

Since we are not mind readers and you do not show us your configuration WITH SETTINGS how are we supposed to help you?

{O.O}