I've had a couple issues recently with performance and my hard drive. The Hard Drive icon lights up and I get drop outs. Is the icon referring to my scratch or my system disk? I pared down the scratch to about 1/3 full (Samsung 256GB SSD) and the system is about 1/2 full (Intel 180GB SSD) but it still happens on occasion.
 
so does the performance monitor refer to scratch or system? I don't have a large sample library on the system, what I have is running out of Kontakt which is a resource hog on the first core. otherwise I *should* have performance to spare.
 
Thanks for the help.
 
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Basics of the rest of system
AMD Vishara 8350
32 GB RAM

A couple of things:

• You can see each drive's IO by opening Task Manager, clicking the Performance tab, and them Resource Monitor. The disk tab will show the activity for each disk.
• Are you running Anti Virus? I've had issues in the past where all of a sudden AV would begin accessing disk in a way it had not before. Maybe it was an update. Try disabling AV.
• Do you have Windows Indexing enabled? That can cause a lot of disk activity.
• Was a Windows update being installed?
• Finally, you call your disks System and Scratch but what is each one used for?

On another note, Kontakt can be set up to use multiple cores in Sonar. If it is only using one core, you probably can change that. I think I have mine set so Kontakt does not manage multiple cores but Sonar does. Using mulitple instances of Kontakt then can spread the load across cores.

It is my understanding that the disk activity monitor in Sonar is measuring the proportion of the disk buffer (for the disk to which Sonar is writing data), that is being filled. So for most people that represents the disk set up to record projects or the "audio" disk in the setup. If that buffer capacity is exceeded then you can lose data, but you can increase the buffer size. This is not the same as the audio driver buffer, but is accessed under Edit > Preferences > Audio - Sync and Caching under File System. Too small a buffer can result in problems regardless of the capacity or speed of your physical hard drives under Windows. 
 
As dRank says, you can get a better view of the actual disk capacity and usage via Windows. I think that an actual shortage of disk space or even fragmentation of the disk is generally not a big problem for most users of Sonar, although defragmenting is frequently advised on the forums. A massive load on the system drives from other programs could possibly swamp the system drives, but again, that should be something you can check in the Windows Performance Monitor. 

Samsung Magician
:http://www.samsung.com/gl...support/downloads.html

When optimizing windows be careful to check the options, you might want to deselect a couple (I didn't just went ahead and it did improve performance for me). Latest version is extremely good (earlier versions were not). Samsung done a very good job here (not bloatware).

Always backup.

Also check out latencymon.

Yeah... crank your Read/Write i/o buffers and it should correct itself.
 
However this does not seem to be something I'd expect from an SSD... but I know jack balls about that shiz. Maybe those Read/Write settings need to be adjusted no matter how fast the drive is.
 
Anyway... I think the default i/o is 256. Doubling it should keep that Perf Module from going red (and avoiding drop outs). I have mechanical HDDs so as a project grows I often have to crank it up even further from there (but we're talking a SHIZLOAD of tracks loaded up with a mountain of takes in each).
 
Edit: and in case you don't know where to set the Read/Write i/o's it's...
 
Edit > Preferences > Audio - Sync and Caching: File System... You'll see two buffer options for Playback and Record. Enter your desired values in those boxes. Don't crank them more than you need to though because that can cause other problems.

This is a long shot but have you ruled out the possibility of a faulty SSD drive.  Have a look in the system event viewer (Winkey + r , eventvwr.msc) for any disk read errors.  I have had a faulty drive that initially manifested itself in short pauses in system operations. I checked system event viewer, and sure enough, there were bad blocks developing in the drive.   Might be worth a look to rule out this possibility.

Excellent responses. Will check everything tonight. I get a clean bill of health from latencymon usually. Never realized that it displays the buffer. It explains why at startup of a project it shows close to 90％, but settles back to 60％　after a few seconds.

Nothing seems to make much of a difference. 
I have an octa-capture with current drivers.
I tried switching between WDM and AISO but that makes no difference. 
I unplugged the focusrite VRM box since it didn't like it when i changed sample and bit rates.
Indexing is off
I changed sample and bit rates to 32/96 and then to 24/44.1
I changed the cache sizes, doubling them to 512.
I have a 18 track file (all audio) on one ssd and i get pops and quick drop-outs. But nothing in sonar or window's performance monitor shows any hiccups. RAM usage is about 5% (i have 32gb installed), CPU is at 16%, Sonar performance says the disk buffer is at 1.7% or some really low number. 
There's nothing in the reports thats critical although it does report some hard page faults.
 
In the past ive run latencymon and i get issues with one windows driver related to USB1, otherwise i'm running a good system. Tomorrow I'll pull the usb card from its pcie slot and see what happens. It's there as a holder of waves and ilok dongles.

Hmmm Octacapture eh?
 
This might sound crazy but try deleting AUD.INI (google for details).
Cheers..

Oh and after this, IF running latest Platinum, go to Sonar preferences and disable - allow arm changes during playback.