I had same issue long for long time and finally fixed after installing windows 8. I never had the problem when my pc was running win xp . After I upgraded to vista 64 and win 7 64bit with i7 processor still have the same problem. I had to deal with this issue for a long time and it was so Embarrassing specially in front of my clients because it usually ends up to restart the pc. After upgrading to win 8 and sonar x3d problems almost solved and i can say %95 is better. I think because win 8 is using all the cores compare to win 7 and some how sonar x3d matches itself with this ability more better.
The other thing is make sure all the plugins you have on your daw are 64 bit compatible and try to get the latest update.
 

Thanks, kristoffer and REZA!   I will do the DPC latency checker.    Not sure about upgrading to Windows 8, but if I need to, then that's what I'll do.   Thanks for the suggestions!
 
Greg

If one track is louder than the others you might have it directed to your outputs instead of the Master bus, Check each tracks output. 

Thanks, Cactus Music! 
 
I did the DPS latency checker, and the "absolute maximum" was 188.   I ran it for about 5-10 minutes, and it said, "This machine should be able to handle real-time streaming of audio and/or video without drop-outs."
 
I don't have my recording computer hooked up to the internet, so I never get updates.  Could that possibly be an issue?
And could the problem also be my interface?  When I first got it, I thought something was a bit off on the sound quality - a little on the dark side.
 
If it's the interface, any recommendations on a good one that's $400 or under?
 
Thanks!
Greg

hmmm. if your DPC latency seems stable (as your description clearly says actually) it should not be an driver issue. 
Did you run Sonar, with the projects, with DPC running? 

kristoffer:    You want me to have Sonar open and run the DPC latency checker?   I did not do that last time.
 
Greg

greg54
Thanks, Cactus Music! 
 
I did the DPS latency checker, and the "absolute maximum" was 188.   I ran it for about 5-10 minutes, and it said, "This machine should be able to handle real-time streaming of audio and/or video without drop-outs."
 
I don't have my recording computer hooked up to the internet, so I never get updates.  Could that possibly be an issue?
And could the problem also be my interface?  

I'm making an effort to address the main problem you posted about in this thread, the CPU issue.
 
Probably the most significant things you can do, now after running the DPC Latency Checker, to help the strained CPU issue are:
 
- Disable core-parking, if not already done (see post #15 on how to do that.)
- In some cases, being up to date on important and recommended Windows updates can improve your system's performance, so it wouldn't hurt to be up to date with windows update. 
- Freeze softsynths or bounce to audio tracks with effects (if you are not currently recording on the tracks with softsynths and effects, they can be frozen or bounced to audio.)
- Raise the ASIO latency buffer for project playback
 
The things listed above are things to do that will allow for less strain on your CPU.
 
For playback and record performance, your audio interface, the Quad-capture is good to go, according to a good number of user reports here in the forums. If you want to make a purchase that will relieve the strain on your CPU even more, purchase another CPU. A faster and more powerful CPU will make a significant difference. I would recommend a core i7 920 or something faster or with more cores.

greg54
kristoffer:    You want me to have Sonar open and run the DPC latency checker?   I did not do that last time.
 
Greg

 
Run it with SONAR closed.

Disabling the core-parking seemed a bit over my head.  I'll have to go through that when I feel a bit more confident.
I'll freeze synth tracks and get updates for windows 7.    Then I'll see what happens and go from there.
You want me to raise the ASIO latency buffer from 256, where it is currently?
Thanks for your help!
Greg
 
 

greg54
Disabling the core-parking seemed a bit over my head.  I'll have to go through that when I feel a bit more confident.

 
In SONAR, in the ControlBar Performance module, does the load look evenly distributed among the threads? If they do, disabling core-parking probably wont make much difference. If 1 thread is far above the other threads, you may do well disabling core-parking. Just follow the guide I posted. And don't forget to reboot after you make the changes. Also note that one thread will always take more load than the others, but one shouldn't be very high and the others very low.
 
The best thing to do is upgrade your CPU.
 

greg54
I'll freeze synth tracks and get updates for windows 7.    Then I'll see what happens and go from there.
You want me to raise the ASIO latency buffer from 256, where it is currently?
Thanks for your help!
Greg

 
Only raise the ASIO buffer size if the strain on your CPU from the project load is causing dropouts, static, pops, and clicks when you playback or record. The idea here is to use as low an ASIO buffer size as possible without getting dropouts when you are recording MIDI using softsynths and recording audio. If when you playback the project, you get dropouts, pops and clicks, raise the ASIO buffer size to a size where the dropouts, pops and clicks stop happening.