I'll check that tonight.
 

The out of sync comment in the OP concerns me most. Is that always the same track(s), and if so, which VST(i)s are on those tracks?

mettelus
The out of sync comment in the OP concerns me most. Is that always the same track(s), and if so, which VST(i)s are on those tracks?

I'm wondering if this has some to do with PDC, where the track timing is off.
I routinely run into this, especially with convolution reverbs, where I add a new Send or buss during playback. I merely have to stop and restart playback, but it does happen.

Someone else with a Focusrite Sapphire has a play/stop delay.

Here's how to run CHKDSK on Windows 10:
 
When you right-click on the "Modern"/"Metro"/"Start"/"Windows" square in the bottom-left corner of your screen, you should get a list of options. One will be either "Command Prompt (Admin)" or "Windows PowerShell (Admin)". Choose whichever one you see that says "(Admin)" in the option.
 
This will open to what appears to be a DOS box, at your C:\[whatever, it doesn't matter] prompt. Type chkdsk /r and hit ENTER. You'll be told that Windows can't check the disk while it's in use, do you want to schedule a disk check? Yes, you do, so hit "Y". After Windows tells you it has scheduled the check, type exit and hit ENTER. Reboot when you have an hour that you don't need the computer (the scan can take a while). When it's finished, you'll be back into Windows again, but Windows will have corrected any problems on your hard drive that it's capable of fixing. It will put a report into the Windows Event Log, and we can check it there.
 
Steve

In that other thread, Bitflipper made a good point that audio buffer size will contribute. The spinning circle/out of sync issue leads me to believe that a VSTi is pulling samples from a hard disk in preparation to stream and possibly internal audio processing as well. Depending on fragmentation of a sample drive, and how many samples are being pulled, the input/output cache for the drive must also be filled before play will start. Running FX with look ahead buffers will also contribute, since they need to know what audio is coming down the pipe to process "time now." All three of these things are additive.
 
The out of sync issue is something to track down, since I have seen select VSTis lose sync with the host, and the issue may be as simple as freezing that particular VSTi. I have noted some which lose sync when stopped and jumping the now time manually, then restarting. In that situation, SONAR is trying to resync time now to where the VSTi "should be," which can get complex depending on how much internal audio processing the VSTi does before passing it to SONAR. Freezing reduces this processing dramatically, and becomes simple audio playback for that track.

I don't use any VSTi's and, no samples. All real instruments.
Didn't get time to try anything out tonight. Got busy with a client.

If you have WIFI, turn it off while using Sonar. It's like getting a new motherboard.

I've tried with wifi on and off, made no difference.
 

Opened a new project with just 1 track, 1 Master bus, no plugins at all..... everything appears to work fine, with no sluggishness. Started adding a BUNCH of plugins (Lots of comps, limiters, and reverbs). No change. Cloned that track over & over. Never really got the sluggishness but, after 21 clones it kept dropping out completely. NOTE: these tracks had about 10 times the amount of plugins I would EVER use! I especially loaded them up with plugs that take up a LOT of CPU!
So, I guess I'm just asking too much out of my computer? I have never seen high readings in the performance meter in Sonar. Isn't that odd?