Not sure if it is something is wrong with my microsoft keyboard, Sonar or Windows (8.1 x64) but lately, Sonar is not responding quickly to my space bar for start/stop when the cpu is very loaded... The mouse and ui controls do work fine but I have to smash the space bar multiple times before I get any response, and sometimes Sonar reads the consecutive key stokes and decides to stop and restart. I did not have this issue when platinum was originally released but I wouldn't be surprised there is something else to blame. Has anyone else experienced this madness?
 
Erik.

I tend to use touch to stop recordings. It is silent.

Sometimes my alpha track hardware controller.

I have seen cases where touching the space bar once was not enough... usually during long sessions. Hitting it harder makes no difference. Hitting it the second time usually does the trick.

Is it possible there is an energy saving feature in the keyboard when it is inactive for a sufficient period?

If it's a cordless keyboard, gswitz may be correct.  Sometimes they put themselves into a low energy mode and the first keystroke after a period of inactivity wakes them up, which adds delay.

Since I now have a wireless kbd, I'm glad I just happened to(when starting out) use the mouse and the record button on the track. I usually have a 2 bar count in so no biggie. If there would be a reason, I guess I was afraid of hitting another key and screwing up everything!

gswitz
I have seen cases where touching the space bar once was not enough... usually during long sessions. Hitting it harder makes no difference. Hitting it the second time usually does the trick.

The keyboard is not wireless and there is no way it went into any energy saving but anyway, this might be somekind of windows issue where everything else has priority over the keyboard with a heavy cpu load.

USB keyboard attached to a USB port which Windows is putting to sleep?

Check the physical keyboard.   Dust or debris under the spacebar?  Broken or worn springs/parts?
 
If all looks good, try a different USB port.

Let me guess... your project is getting bigger and bigger possibly with lots of takes... right?
 
That little bit of delay before playback is Sonar preparing itself for any possible editing changes during playback (like comping). It happens to me all the time as my projects grow. At the beginning playback will start immediately, as I track it gets slower and slower until sometimes it's a full second or more before playback will start. That's usually when I do a massive cleanup of the project (flattening/bouncing comps, deleting unnecessary takes/tracks, Archiving anything I don't need but don't want to delete, etc). Once I do those little housekeeping procedures the project starts responding quickly again.
 
Smashing on the keyboard muliple times is definitely not the way to go. You're just asking for a crash and more general aggravation than just letting Sonar do what it needs to.
 
Cheers.

BTW... just curious, did you upgrade to Platinum from a pre X3 version (as in X2 or earlier)? One thing I noticed is the introduction of Comping in X3 really made this issue become more pronounced. It is getting ready for very fast clip status changes (muting/unmuting/promoting on the fly) whereas before, even though you could KIND of work like that it wasn't recommended workflow.
 
I am not sure because I handle it in other ways but maybe switching out of Comp mode might help.
 

The function of a physical keyboard is easy enough to test. Use a fast responding text editor like notepad and see if you have the same problem there. I assume you do not have USB suspend enabled in the power options on a DAW.