SHS4 Audio Engine performance

Now having both versions (HOme Studio 2 and SHS4) I did a rough comparison on audio engine performance between the two by having exactly the same projects running and compared what I'd think might indicate performance, the CPU utilization reading( % ).

I ran two different projects at 10msec latency, one midi only, with 5 soft synth instances: 2 GPO's, 1 sfz+, 1 VSC and 1 ST2, most of them with full patch loadings. The second project was an audio only project which consists of 27 tracks and 24 real time plugin effects, among them very CPU stressing such as GPO ambience, Sonitus multiband, several instances of sonitus equalizers and 2 instances of Glaceverb among others.

When I ran these two identical projects in both Home Studio 2 and SHS4, there was not clear difference in performance, not on CPU usage stability and not on CPU average and peaks, in both versions CPUs % got lower after the first playback.
I was expecting clear better audio engine performance indication on SHS4 as it is the same as for Sonar 4 but based on the way I measured, the result is that this is not true (at least on my system).

My question is as follows:if the new engine is more efficient, how is it being reflected? otherwise why have I been misled about this important feature?, so I wish Cake would be able to clarify better the audio performance advantages (if they are) of SHS4 over older versions.

I know what you mean but that doesn't have anything to do with audio engine performance. What really happens is that those plugins (SIR, CurveEQ, etc) use a look ahead buffer to be able to process so they create a certain latency in the signal. Sonar automatically does delay compensation (ADC) so this delay doesn't have to use the system effective latency to process the buffer. Older Home Studio versions do not have this feature so you can't run the same plugins at the same latency as in SHS.
IMO the best way to compare performance is on CPU readings at constant (low) latency values and check with both MIDI and audio work.

Thanks Jesse for the clarifications. I have been probably misled by some forum (sonar and Home Studio) posts indicating a clear advantage of the new engine as of improving system latency and better utilization of the system power. Based on what you're describing, that might not be the case. However, I do appreciate the type of advantages that you described.

I'm not sure about performance, but I do know that (on my system) SHS is much more stable. HS2 (and earlier incarnations) would intermittently freeze. I would have to shut down HS, restart it, and close it again in order to get it working properly. I haven't had this problem with SHS.