When I open X1 or X2 , when I look at the performance window there is no CPU movement.
On X3 after opening I see a lot of CPU movement in the window.
 
Is there an explanation for this ?
Does Sonar use a lot of CPU even though nothing is playing and nothing is being done?

Are you opening the same project?
And what's it like when you playback and record?
Also temporarily disable your virus scanner.
Why are you running 32 bit windows?

Not the same projects. I get more activity with playback and record and I only use the windows security on the computer.

In support of CowboyDan's question, I took 2 screenshots...
 
First, Cakewalk Sonar X2 at rest using no processor...
http://stabilitynetwork.blob.core.windows.net/g-tunes/Screenshot%20(13).png
 
Second, Cakewalk Sonar X3 at rest using 2.4% of the processor...
http://stabilitynetwork.blob.core.windows.net/g-tunes/Screenshot%20(12).png
 
For the X3 image, I waited for a while to see if I could get the host to go quiet, but it did not.

Ok to be clear is playback and record worse with X3 than it is with X2?
 
Please use the same project so you are comparing eggs with eggs (open X2 project, save as X3, open it again) to see if this makes a difference.
 
Please disable virus scanner when you are opening the projects (not sure what you mean by "windows security", but if it's security essentials then that is a virus scanner).
 
... and do a defrag first.
 
Then you may have a point :).
 
Cheers...
 
Alex
 
p.s. Why are you running 32 bit windows you realise you are not addresssing all of your memory above 4gb?

p.s. Geoff you are running 64 bit windows not 32 bit, so not exactly eggs comparing with eggs, but I get the point.... I suggest checking out what I said though here and in the other post to make this a little more scentific:
http://forum.cakewalk.com/Lag-switching-between-projects-m2939170.aspx
 
The other thing is that nobody here is stating how they are opening their projects. Are they opening sonar and the project at the same time from windows, or are they opening sonar, waiting for a minute, then opening a project?

He Alex
I am also running Windows x64. I have no issue with the sound of the tracks or anything as far as that goes. It just seems strange that with the same setup (computer, sound card, etc) in x2 gives nothing in the performance windo with cpu cores and with X3 I have all cores jumping around without doing anything.
BTW I just start Sonar and wait for the Quick Menu and then open the file. I hope just like everyone else.
I also have 16Gig of memory working as to not have the CPU working too hard.

Ah you've written Windows 8/32bit in your header, so it's 64 bit :)
Anyway you may have a point, I would recommend though going through the optimizations in this post and the other post to see if it makes a difference first before we can point at a smoking gun.

Preferences > Audio > Playback and Recording > Always Stream Audio Through FX.
 
This setting  and functionality are new to X3. X1/X2 will behave similarly after you start and stop playback once, enabling the audio engine. But the idle load will still be lower because it doesn't stream silent audio through all FX all the time. The advantages of doing this are documented in the New Features section of the Ref. Guide.

I didn't know this, thanks for the tip Dave. Let's see if OP reports back that this makes a difference.