Rather than rely on System Restore, I have been relying on good backups in case of problems caused by installing new software or whatever. I do not like the idea of renaming files, which sometimes happens with system restore. But today, I setup system restore on my C drive, which I thought would be no problem, because my data files are elsewhere. Even though I had a very small amount of memory allocated, I seemed to experience some degradation of sound when using GPO with Sonar. I switched it off, and the GPO sound returned to normal.
I am wondering if this is a peculiarity of my PC system, or if the System Restore function generally causes degradation in some form.
My solution is simple. Since I don't need it if I had good backup, switch it off permanently.
System restore works in the background squirrelling away files so consuming your PC resources while you are working. If your system is 'on the edge' when handling its audio apps, then indeed any background service could start to push Sonar 'over the edge' in terms of performance. How different sequencers behave in these circumstances is interesting. Sonar seems to initially try to 'conserve' resources by playing back VSTs at lower quality when under pressure. If that fails it starts to not bother playing some tracks at all. In some ways I prefer Cubase's 'give up the ghost when the going gets tough' approach.