Hey Todd,
 
Fellow SONAR/Apollo/UAD user here, can't say I am experiencing your travails, but I think you are on to what is causing your issues. I typically build my own DAW's and as you probably are aware there are certain tweaks you need to check/do when setting up a DAW for realtime audio performance use. If you have not already you may want to watch this insightful video that may point you in the right direction to solving your dropout issues. You can have the most modern and fast 8 core i7 computer, but if is not set & optimized correctly for realtime audio performance it can perform worse than a 25 year old single core Pentium 3.
 
Good luck,
 
https://www.youtube.com/w...=416&v=GUsLLEkswzE

todd_bates
For the love of....
 
So my joy lasted exactly one reboot.  As soon as I rebooted my system the same old garbage started happening.  Back to being a sad pup.

That would seem to indicate there's some Windows preference or service being restored upon bootup. Open Task Manager and take a look at your startup programs. Since you built your own computer you won't have the bloatware included in something you bought for cheap at an office supply store, but still, I'm sure there are things like "iPod Helper" or whatever that you can nuke. 

Thank you all for the great tips and advice.  Sadly nothing is panning out.  So here's the kicker...
 
I downloaded a 60 day trial version of Reaper.  I wanted to see if a different DAW would make a difference.  Reaper recognized my Apollo in seconds, configured using only defaults (256 latency) allowed me to import all my Sonar wave files and then let me add plugins (UAD, WAVES, and SONAR) to the mixes in real time while the songs were playing with no glitches, no dropouts, no crashes...perfect mixing experience.
 
I tried to stress test the system and worked on a song with 35 tracks and 9 sub mixes and each track had at least one plug in that I added in real time while the song was playing.  When I reached 75 plugins with no issues (adding them as well as making edits to the eq, reverb, delay, etc) I stopped...I was convinced.
 
Reaper is working for me with a reasonable look and feel, can do all the basic functions I could do in SONAR and I can focus on my mixes and plugins with no issues.
 
I hate to say it, team, but for me, personally, Reaper is kicking Sonar's hind quarters and the issue on my system with my setup is Sonar.  Reaper just proved that to me.  I am not pitching Reaper to anyone, just saying I haven't had this kind of stability in a long time.  I just wish it could have happened with Sonar and not a 60.00 software package.

Hi, Alan, sadly Sonar has given up on me.  Been with them a long time but support won't answer my requests for help.  UAD has sent me two emails already asking what Sonar had to say but it's been a cold shoulder from Cakewalk support.  Still kicking butt with Reaper, though.  If Sonar would help me resolve this I would be glad to switch back but I don't have the time nor the patience to wait months and months for them to even send a message back...even one saying "sorry, charlie".   Truthfully, I don't think UAD and Sonar work well together and I suspect that's why there's not a lot of communication coming from Sonar Support.

Those are good thoughts, Alan, and I agree, Mr Anderton always has great input.
I made it a point to purchase only items that met the UAD specs, so I am comfortable that I meet UAD system best practices.
 
 I would never have guessed that Sonar would be he stumbling block for my situation, but things work perfectly on another DAW so that is hard to think that my computer or UAD is the issue.  I used to use a Liquid Saffire firewire interface and a UAD quad card on a less beefy computer and had far fewer issues.  Who knows, maybe Thunderbolt is the problem.  Maybe Sonar doesn't like working with an Apollo Thunderbolt for Windows unit.  Sigh.  Just watching the posts hoping for a miracle.
:)
 
 

Hi,

Having a similar experience with an Apollo 8 Thunderbolt; being a sonar user for years and got dropouts every start/stop. Unable go lower than 512 buffer size if *i want to be able to work with normal decent projects (20 tracks with virtual instruments and audio, processed through existing plugins, nothing too fancy). Even if the DPC latency reports very good measures (lower than 100) I still got dropouts... I tried with Studio One and got some weird results that I did not explain either until I decided to go deeper and rearrange the graphic card on another PCIe port and my SSD drives through the same interface. Now everything is super smooth on Studio One up to a buffer size of 32 but I still have the same results with Sonar. I will try to stress up the setup with Studio One to see how it behaves on heavier situation but I do think something is wrong with the way Sonar deals with TB interfaces.

I will also try to give a shot on how Reaper behaves on my system too...

Best,
Stéphane

MB used: Gigabyte Designare EX X99