If the driver update fails to resolve the issue, I would still press support for resolution. Verify Preferences > File > Audio Data "Record Bit Depth" has been set to 24. Might want to tinker with Preferences > Audio > Sync and Caching "Record I/O Buffer Size" the sweet spot is system dependent. Also dial back the dropout sensitivity variable DropoutMsec (I set mine to 750 but have no idea what to set it to in this case) in Preferences > Audio > Configuration File. There are other config file settings which may be of interest FlushWriteBeforeRead, FlushMultiple, EnableCacheWriteThru but would defer to someone more knowledgeable about the impact of these parameters in this setting.

Probably already covered above, but if you drop the bit depth to 16/44.2, are you able to exceed the 64 track barrier? That would suggest hard drive I/O bandwidth, and not a 2^6 problem in SONAR...

Like I said, 72 tracks is like 18MB/s, no way should that be even near the limit of any SSD. It's always possible something weird is going on in your system but so far that Tom's Hardware thing supports what I was saying.
 
I'd definitely try updating the driver if you still haven't.

Not only drivers, check to see if there is a firmware update.

Hi Danny,
I happen to have a mutli-input sound card with enough inputs to replicate what you're doing and, while it did tax my system pretty heavily, after tinkering a a bit with the File System options (under "Preferences" - "Audio" - "Sync and Caching" was able to record 70 tracks simultaneously to a SATA drive (not an SSD) with good reliability. I didn't let it go for too long...a minute or so, but I was able to do more than 64. I'm using an RME HDSPe MADI fx, so we have some different hardware, but it did work.
 
The preferences tinkering I did was really to solve the disk overruns that I was getting at first. I didn't seem to run into a track count limitation, just a "my disk drive is too slow to do this" limitation. When that happened I got a specific error about disk overruns.
 
I don't know that I can offer much by way of help for your scenario, but knowing that Sonar is capable of doing it is at least a place to start. 
 
Good luck man, sounds like a big project you're working on.
Dean

Lest anyone think I've skipped town, I am paying attention.  I just have to work a different job on the weekends and it's in the way of getting to work on this.  I sure do appreciate the help and will get back to it as soon as possible.

Last thing done was to update the driver for the three Lynx AES16e-50 cards from version 13 to 13.1 but I haven't had a chance to work with it yet.  I'll be back.  

Dean, it's good to hear that greater than 64 tracks can be recorded.  Appreciate the test.

Maybe the problem ist the preview drawing of the waveforms while recording.
Ist not only 72 tracks of audio - it's PLUS 72 previews.
Go to the preferences (Customization - Display) and de-click preview while recording.
 

Hi Danny,
 
Do you have the SSDs connected to an Intel SATA-III controller?
3rd-party SATA controllers work ok... but they won't give you the full performance of the SSDs.
 
I'd test writing to a single SSD (AHCI mode - not RAID)... to see if you still get the dropout.

• Backup the SSD RAID Array
• Switch the controller to AHCI
• Reformat the SSD

The 840 EVO SSDs sustain over 500MB/Sec when connected to an Intel SATA-III controller.
That should be plenty of speed.  Bandwidth certainly isn't the issue.
With RAID, you're increasing bandwidth... but access time may be increasing just enough to cause a data-flow "hiccup".
 
I'd absolutely update the driver...
 
 

Not sure about your issues completely, but I though I would ask.
When you installed the OS on your raid system drives, Did you unplug the other HDs or SSDs drives from the motherboard?
 
I read on the Crucial website forums that when installing to ssd drive a  win 7/8 os, to remove all other Hard drives and ssds while doing so, and updating the os and drivers...then plug in the other Drives....as windows will put swap paging filing on them on installation...which could cause Page fault errors, and logging of those errors to event viewer and such....ect.
 
Just something I thought might have relevance to your issue?.....Just thinking outside the box....not saying it is your issue...but one I read on, with ssd drives as system drive.
 
Wink.. here is what I read: 
 

Re: M550 Boot Drive Installation

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‎04-19-2014 03:23 AMin reply to targetbsp
I did find a solution aftrer installing Windows 8.1.  I have three internal hard disk drives and that was the problem.  When installing Windows 7 or 8 onto a new SSD boot drive one must disconect all other internal hard drives.  Otherwise Windows will attempt to change the number of sectors on each drive to match the number on the SSD.  Therefore, disconnect all internal hard drives, install Windows on the SDD and then reconnect the HDDs.  Once that is done it may take WIndows a few hours before it recognizes the other drives but it will. Once that occurs then the installation runs perfectily.  It is rather odd but does work nicely.
 
Thanks for the help.
 
Bob

http://forum.crucial.com/.../highlight/true#M41971
 

I have to induce serious caching to get more than 40 tracks to Play/track, since I use 2-3 plug-ins on most channels. I believe the faster the hardware gets, the fatter the software develops. It's a never-ending battle. I'm hoping one day in the future, the hardware will be cheap enough to handle 10-times the amount of software without any problems. But we have to limit new features to get there. That's my observation, anyway. PT has always required external DSP hardware to do what it does, and that's still the case today for large productions. It's just less required for smaller sessions.
 
I think recording 64 tracks at 24/96 in the current speedy desktop PC and existing home-studio hardware is still a lofty goal. I've not seen it done yet, myself. Maybe it has, but with current Motherboard/CPU hardware speeds, I'd love to be able to track 72 tracks. Many claim they have done it. I don't see it. Perhaps with literally "everything" else disabled you could?
 
"Mack the only way to get you on a chopper that far North, is to strip it down and turn it into a flying gas can!" -From Hunt For Red October