AFAIK Core Parking does tend to only work with HT. My i3 used to park 2 cores, but my i5 doesn't regardless of settings. Many others say the same - they're seeing "parking" on i3 & i7 but not i5's. Core Parking is best disabled unless you're running a Xeon with more than 4 real cores. Aside from the fact theoretical power savings don't pan out in practise (ie, park the HT 'cores' on an i3 and the 2 real cores get loaded slightly higher which translates to fewer downward SpeedStep transitions under medium loads which translates to wiping out the "lower" power consumption from disabling HT)...
...There's also a bug where Core Parking doesn't properly unpark HT cores under some demand loads for some reason. I experienced this on an old i3-530 with the following scores in WinRAR being the most striking:-
CP Enabled - 2,924kb/s
CP Disabled - 3,609kb/s
23% is a huge performance loss, and I'm certain is one main reason why some heavily multi-threaded games (BF4, etc) see a Windows 8 vs Windows 7 difference with HT CPU's. Parking cores isn't that much more efficient than current C6/C7 states which already gate down large parts of the CPU when idle whether they're parked or not.
The other thing you're talking about (CP involves other performance non power related stuff) is a load of bunk to be honest. I can only assume the writer confused it with something else as disabling cores (even virtual ones) is something that's rarely going to make a PC faster (and you can get exactly the same effect on an i3/i7 simply by disabling HT in the BIOS).
As for Windows Power Saving Settings:-
"Minimum processor state" and "Maximum processor state" are to do with SpeedStep. Changing them adjusts which SpeedStep "P" states Windows will use for idle / load. Eg, on an i5-3570:-
5% = 1.6GHz
65% = 2.2GHz
80% = 2.6GHz
90% = 3.0GHz
100% = 3.4GHz
Setting "Maximum processor state" to 90% and leaving minimum at 5% will cause Windows to use the 1.6-3.0Ghz range. Setting "Minimum processor state" to 65% and maximum to 100% will cause Windows to use the 2.2-3.4GHz range. Default for "balanced" is 5-100% (1.6-3.4GHz). It doesn't affect core parking or HT, it simply overrides which SpeedStep "P" states Windows treats as min/max for idle/load.
"Processor performance core parking min cores" & "Processor performance core parking max cores" refers to the minimum & maximum number of unparked cores allowed, ie, setting minimum to 100% will disable core parking. Setting to 0% won't force park all cores though as Windows won't do that. It applies more to CPU's with HT than without. You're better off disabling Core Parking in general especially on a CPU with HT as it does cause issues with some apps (WinRAR being one of the worst hit for some reason).
By default these settings aren't visible in Control Panel on Win7, and you have to either use the following tweak:-
http://forum.notebookreview.com/asus/494232-how-adjust-core-parking-inside-windows-7-a.html
Or better, use Park Control and tick the "Show park settings in Power Options":-
http://bitsum.com/about_cpu_core_parking.php
Not sure if this answers your question, but basically, Core Parking disabling cores has never had any positive performance impact on remaining cores, only a negative impact (mostly with HT cores).
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