The Core Speed that CPU-Z reports is a meaningless number when a CPU is throttling internally. Before trusting any monitoring software, why not see if it can pass both of these tests?
Here is a Core i7-4700MQ running the Super Pi Mod 1M benchmark. It has taken 9.910 seconds to complete the first 19 loops of the calculation. I think that's a reasonable time for a properly running 4700MQ. CPU-Z reports that the CPU is running at 3495 MHz.
There are 2 types of throttling that are used in most laptops. Intel designed these so a CPU could be quickly cooled down but unfortunately, some manufacturers have decided to overuse throttling. The two main types are clock modulation throttling as well as chipset clock modulation throttling. Either or both of these can be used and they will instantly kill performance when they are engaged. ThrottleStop is the only tool I know of that can detect and report both types of throttling.
If you look at the above screenshot, ThrottleStop reports both types of throttling are at 100.0% which means the CPU is being allowed to run at its full rated speed.
In the second example, the same calculation as above has taken 1 minute 33.599 seconds or 93.599 seconds.
That is over 9 times longer. CPU-Z shows 3391 MHz. The CPU is severely throttling and CPU-Z barely reports any difference. ThrottleStop correctly shows that each thread of the CPU is using Clock Modulation throttling and each thread is running at only 12.5% of its rated speed. The C0% is another warning that the CPU is not running as it should.
The next example shows what is reported when an Intel CPU is being throttled with Chipset Clock Modulation throttling.
Once again a calculation that should take less than 10 seconds has taken 93.199 seconds. Serious throttling is in progress and CPU-Z reports 3491 MHz.
Why does the user community depend on CPU-Z if it cannot tell you whether your CPU is running at full speed or if your CPU is being throttled to death?
Turn CPU-Z off. When a CPU is throttling, it is not the tool for the job.
Besides throttling, some laptops also use the bi-directional processor hot (BD PROCHOT) signal path. This allows sensors on your motherboard to signal your CPU and trick the CPU into thinking it is too hot. When this happens, the CPU responds by dropping the CPU speed down to approximately 800 MHz. If a sensor has gone bad, the only way to properly fix this is with a new motherboard. If the warranty is up then I would suggest using ThrottleStop to disable BD PROCHOT. This prevents these external messages from getting to the CPU. When BD PROCHOT is disabled, the CPU will still be able to throttle if it ever gets too hot.
Use ThrottleStop to disable all of the various throttling problems that your laptop manufacturer has saddled your laptop with and rerun the Intel Diagnostic tool. You should see the green flag after that.