I´m having the same issue, X3 is a about 20% more cpu hungry than X2.
 
Just tested with the same Project on both...
 
In projects that before I was on the limit (60% cpu usage) ...on X3 now they are about 75% and I start to hear "clicks and pops". This is with the same buffer size and latency. On another project ..X2 was 18% CPU and X3 25% CPU.
This is in a quad core I7 920
 
Anyone solved it deleting the AUD.INI file??
 
Daniel

Deleting the AUD.ini file has solved various problems for me, done it more than once! IMO it wouldn't do any harm to try it.

Bibs

I would recommend renaming instead of deleting in the event that it doesn't help - that way you have your original settings still intact.   For that matter, even if it does help, you can still compare the old and new settings to see what's changed. 

guigz2000
Yep...The aud.ini file is the file which stores all the audio configuration infos.
it's located in
C:\Users\XXXXXXXXX\AppData\Roaming\Cakewalk\SONAR X3 Producer
 
You can access it in sonar using advanced mode in preferences,audio section (4th subsection)
When you install X3 over a previous install, it will import previous config files. It may be good to delete(rename to keep backup) it to have X3 rebuild it and be "Full X3"

This is good advice.
 
I did this as part of the X3 install and the aud.ini file shrank from 6Kb to 2Kb.
Of course I still have the original if anything does screw up, but so far it's been flawless.

Thanks for the tip. I wasn't having any problems but I want to have the best settings possible for X3. I followed the above instructions. The aud.ini file went from 6kb to 3kb. 

Since this seems such a "fix all" I wonder if there isn't (or shouldn't be) a "reset" button somewhere in the preferences.

The need to rename the AUD.ini does not happen that often. There are a couple of other "reset" options.
 
Opening SONAR while holding the SHIFT key will force a resync of your application data to the current user. A typical use is to fix "Missing Master.ins" message.  Note this is different then opening a project holding the SHIFT key which invokes the SAFE Mode.
 
Opening SONAR while holding CTRL+SHIFT  "re-personalizes" SONAR overwriting application data and reseting some registry keys. This is pretty much the "reset to factory" option.

Yep, same here...CPU core 1 appears to be working harder than in X2. I recently trialed the Lush synth plug-in and my CPU shot through the roof with lots of pops and crackles...lot going on there. I usually run Maschine and if it's also using Massive, I'd been assuming this is the reason as well. Will try re-naming the AUD.

scook
The need to rename the AUD.ini does not happen that often. 

Yep. If you consider the renaming will force X3 to rebuild audio settings, there's no point in doing it multiple times, unless you are changing your hardware or there's an X3 update. If that's not the case, you'll just create the same aud.ini over and over and won't get any benefit.
 
The initial renaming is done only to ensure there's no X2 configuration infos anymore. So, if you get problems after a aud.ini rebuild, you should try to tweak settings instead of expecting a rebuild to correct them.
 
People should not forget too that sonar may not be the problem. Vsts are plugins which are eating power and may be buggy in certain conditions (especially when using bitbridge) . You can't just stack 10 of them on each one of your 40 tracks and expect that you'll get your 400 plugins running with latency compensated  and consuming only 10% of your main cpu core. Freezing tracks is there for that reason.