Opinions: Which version of Sonar was the MOST CPU resource friendly?

Like the question says, which version was the least CPU resource hog.
 
I have been a Sonar user since Sonar 3.  The reason I ask, I am considering using Sonar in a Live setting.  Right now my performances have been  primarily in a Church setting.
 
Lately I have been using my lap top to log into the Church's network to have access to the Net and the cloud, for rehearsals.  So my hope is to have my Wifi card turned on and my primary Synth's of choice at the moment are Garritan Authorized Steinway, Lounge Lizard (Unfortunately X3 only), Dimension Pro and maybe Rapture.  At most I would have three of these loaded at the same time.  So far, under X3, my i5 lappy hiccups.  Dropouts, clicks and general all round burps! It's difficult tweaking the laptop at the moment for top performance, especially if my wifi card is on, although I would turn in off when we go live.
 
So, I am trying to use the best version of Sonar, strictly for playing VSTi's for live performance.  This may ultimately turn into playing along to a prerecorded drum/percussion loop and click track for the drummer or whatever.
 
Just to clarify, I have never had any real show stopper issues/glitches with any of the Sonar versions, so we can eliminate this from the discussion.  I seem to recall really liking Versions 3, 6 and 7  What are your opinions on this?
 
Rich

Steve,
I realized in my haste that my question probably wasn't fair since I referenced sonar 3.  Taking the multi-core processors into account I should probably throw S3 out of my list of favorites.  Thanks for your opinion and response.
 
Rich

W

For me from 4.0.3 through 6 it was about the same. I didn't look at anything after 6 until X3.
I have no wireless running or installed.
Finished projects that used to play flawlessly at 1.5ms and 2.9ms needed to go to 11ms or above to play.

Not the case here. My network never causes any issues.
In fact, when I'm working on my old 4.0.2 rig I'm often enough running 16 ports of MidiOverLan and using 3 Giga Studio satellite machines, running 128+ midi tracks and at 1.5ms latency with never a glitch.
 
 
 

...I've had no reliability issues with any version - minus a few driver bugs from time to time.
 
I also run X3e on a Win 8.1 machine (i7 w/ 32GB RAM) and have zero stability problems with wireless enabled.  Never even been a thought to turn it off when tracking and I've done a couple 20+ channel projects with lots of plugs pushing around 75-80% CPU.  I run SSD drives as well.  One for the OS and then Sonar is installed on another and finally another SSD where the music is getting saved.  I have a larger SAS drive that I use for general storage, etc...
 
Seems to work great for me...