Nothing major here
 
Rafone

I have very few problems with X2a. The one that is a problem is the crash when clicking on the buss in the CV when it is floated on to the other monitor. I avoid this and no crash. I also always have a saved version of the project
 
I also have the built in audio chip operative and use as the general media device. All Windows sound go through it including multimedia movies and such. I have a separate audio system for DAW use. It stays setup for Sonar and other DAW software. I do not use it for daily general use.
 
I run Windows 8 Pro 64 with no problems at all.
 
For me X2a and Windows 8 are working well. Of the two Windows 8 is solid as a rock. X2a is almost as solid but not quite there. 
 
My point here is that the first thing is to be absolutely sure you have a solid system to begin with. This includes memory and enough of it, graphics cards that have quality hardware components fast enough hard drives with enough free space and a well installed OS with all its updates. Then use your DAW separately for normal or general computing.
 
Ideally a dedicated DAW computer is the preferred way to go. If you are not handy with the ends and outs of computer hardware let an expert help in choosing an appropriate model or better, let a system builder like Jim Roseberry build you one. 
 
Over the years I have come to respect Jim to the point I feel completely safe in recommending him at any time. 
 
   
 
 

No crashes or drop outs here either since x2a. I think part of the recipe is finding the sweet spot of your system.

My system is HP PC with i7 running windows 7x64 with a Cake firewire interface. I try to use only sixty four bit plug ins, but still use a few thirty two plugs. Mixture of midi and audio tracks.

Like John, I use internal sound card for windows, etc.

Just got done doing a 5 song CD project using X2a. This is on an i7 with 16 gigs of RAM using an Edirol UA 101. SONAR was great for me, used the console emulators on everything, mostly used Pro Channel stuff instead of my old Waves bundle. There were multiple soft synths, Dim Pro, Tru Pianos, Kontakt, plus multiple instances of Amplitube and Guitar Rig 5. The only issue I had was caused by Drumagog which was pretty much the only 32 bit vst I used on this project (with jBridge). I had a few crashes due to the fact I was using Kontakt through Drumagog's plug-in hosting feature for the Abbey Road drums which used a lot of RAM and couldn't see the higher RAM addresses due to the 32 bit limitation. I blame all this on the Drumagog guys, and while I love their software, their lateness to the 64 bit party on PC is inexcusable at this point. Overall I was/am quite happy with SONAR X2a on this machine. This was one the biggest, warmest sounding projects I've done yet. 

No problems with X2a here, and I use Pro Channel to some exent on pretty much every track and bus.   I'm running Win7 x64 on an older Q9300 w/ 8GB RAM, a Focusrite 18i6 and a BCF2000.  I use mostly 64bit plugins but still have a place for the occasional 32bit plugin as well.
 
 
 

Hi aixmusique . . .
Since installing X2 (then updating to X2a) on a new computer system, I can count the number of Sonar related crashes on one hand.
When it has caused a crash, I can't reproduce it, in other words who knows ? . . . move on.
Everything I have learned about making Sonar run smoothly, I have discovered from reading this forum.
My PCI slot soundcard is over 10 years old. I use lots of midi, multiple soft synths, audio recordings, all 64 bit plugins, and do my mastering in Sonar as well.
Configuration in Specs below.

The things that will always crash Sonar X2 for me are Vvocal and Rmix.  If I stay away from either of those, I can work for hours without a problem.  Interesting that it's the Roland add-ons that give me the most grief.  Just having Rmix in a project will make Sonar crash randomly - I don't need to be working in its UI.

Since i started using 64bit plugins only i havent had a single problem with X-2a.

aixmusique Who works with Sonar X2 Producer without crashes and dropouts on PC?

Me! 

specs below