In the past I used the DPC Latency Checker
http://www.thesycon.de/deu/latency_check.shtml  
 
It seemed to work fine and gave a easy to understand reading. Red spikes, problem etc. But it doesn't tell you where the problem is. It also now gives a false reading in Windows 8 so we move on to using Latency Mon. 
 
http://www.resplendence.com/latencymon
 
I miss the little green graphic which I used to run on a second monitor while working if I was having drop out issues etc. Those days are gone and my system runs smoothly. I can see the 4 little core graphs in Sonar and they never move above 10%. Memory is at the most 20%. 
 
 
 I'm in the habit of running Latency Mon periodically to make sure Windows is not misbehaving without my permission. It has been giving me the Green light, but yesterday I ran it and it's mumbling something about Core Parking again. It did that a while ago too. My Cores are all running just fine as far as I can see. All power saving features are nuked. 
 
 
So question.  
I've never found the place to disable core parking and it seems not to be required any more. Should I be worried? Where do you do this if so? 
Is Latency Mon accurate?   
 
 
 
 

Min/Max Processor in Power settings (under control panel) should be set to 100.
 
Also check your BIOS setup for Intel speed step, if it's there turn it off. There may be another way to do it in more modern PC's.... If it's off the Min/Max settings in control panel will probably disappear (I think).
 
There is also a registry hack for Windows if you google it (google registry windows "core parking" I think), shouldn't be necessary though if you turn off Intel Speedstep/Powernow etc... You could try both/either/or as an experiment though.
 
Also consider updating your chipset drivers on the Intel driver update website and your motherboard firmware (on manufacturers website) as maintenance ....
 
Ta...

I switched off core parking via the registry in Win7 and disabling all cpu power saving/speedstepping in the BIOS. The Win8 upgrade left it off but the Win8.1 upgrade or a subsequent update switched it back on again. I spotted it because X3e suddenly decided I only have two cores and hammered them to death. The power scheme has cpu set to 100% for minimum and maximum.
 
The Windows resource monitor showed all 8 virtual cores at "100%" but only two of them (0 and 1 I think) showed any activity at all. I checked the registry and found core parking was switched back on there. Editing the registry did the trick and switched parking off again. Interestingly this has the side-effect of permanently enabling the cpu's "turbo boost" feature resluting in mild overclocking to 3.5 or 3.85GHz (still within the cpu specification) depending on which box in task manager you choose to believe.
 
So on my system at least Win 8.1 does seem to need the registry change and it's also worth keeping an eye on things in case Microsoft helpfully switch it back on again for you.

Thanks I'll go and poke around and I'll look up the registry edit "how to". 
As I say Sonar seems to run perfectly fine.