You could try
Intel's MacCPUID to see which frequency the CPU is running at. In the application there is a "recalculate" button that I guess can be used to check if the frequency has changed (it doesn't do it in real-time). I don't have any frequency stepping on my computer so I can't test it.
Unfortunately that app does not show the actual frequency. It only shows the base frequency.
You can check if turbo boost is enabled without installing Windows. Open the Console.app (in utitilies) and then click on All Message. In the search box type in "AppleIntelCPUPowerManagement"
Look for a line that says:
11/07/2012 21:50:47.000 kernel: AppleIntelCPUPowerManagement: Turbo Ratios 889A
(This is from my rMBP)
Depending on the computer, the ratios will be different. For example my 2011 MBA has 008B
The way you read this is turbo boost on 4 cores/3 cores/2 cores/1 core
So on the MBA... the first two zeros make sense, since it only has two cores. The numbers are hex and you times them by 100 MHz. Therefore the MBA has 800 MHz turbo boost enabled on 2 cores and 1100 MHz on one core (B = 11 * 100 = 1100 MHz). Effectively this means that the MBA is running at 2.6 GHz turbo boost on two cores and 2.9 GHz turbo boost on 1 core, which matches Intel's specifications.
The rMBP 2.6 has 800 MHz on 4 cores, 800 MHz on 3 cores, 900 MHz on 2 cores and 1000 MHz on 1 core.
So it's 3.4 /3.4/ 3.5/3.6 on 4/3/2/1 core(s) respectively. This again matches Intel's specifications. If I recall correctly, the last time Apple released computers which had CPUs with disabled features was in 2010. I am glad that they've stopped playing these games.