E220s with i7 - CPU usage max 30% in Firefox and some other programs

I have E220s with Core i7 processor.

I've noticed that processor usage maxes at around 25-30% in Firefox. For example, if I open Firefox with many tabs the CPU usage maxes at around 30% for some 30 seconds until all the tabs load. During that time Firefox is quite unresponsive, scrolling especially. It is not just at startup but during browsing as well, Firefox simply doesn't use the full CPU when it obviously needs it, it just feels like using a much slower computer.
But if I would, during that time, do anything else in Windows or other programs the response would be instant, everything is fast, full CPU is being used.

I've checked with CPU-Z, and the CPU goes up to 2300 MHz during the time Firefox is loading tabs, but the processor usage simply tops at 25-30% even though it is obviously lacking CPU power, it needs more time to finish anything you throw at it.
This is on both, A/C and battery.

Google Chrome, for example, uses full 100% of CPU when needed. The same tabs load in 5 sec upon startup, and the browser feels responsive during that time or any other time.

I thought this CPU throttling was specific only to Firefox, but I've noticed it in some other programs as well, CPU usage maxes at around 25-30%. But some work fully up to 100% CPU.
Really strange, as if some programs can't use the processor fully?

Any idea what could be the reason for this CPU limiting behavior??

 

Make sure you're using the latest drivers (Including BIOS) and make sure your Power Management setting for the CPU are at Adaptive or Auto.

Just for kicks; Does the problem still happen if the CPU is set to high?

One thing you could is starting the Task Manager, go to the "Processes" tab and set Firefox's priority to "High."

Lenovo seems to have a few models with odd throttling problems. Hopefully this isn't another example of this.

 

Yeah, everything seems to be OK - BIOS and all the drivers are up to date, and all the settings are normal. I've had this problem since I got the laptop two months ago.

It happens with any power plan, Windows' Balanced or High performance, or any Lenovo's power plan.
I just tried to set the priority to high, and even realtime, but it's still the same.

Whatever the plan, even if the CPU goes to Turbo at 2.3 GHZ (normal is 1.5 GHz, ULV core i7) or is throttled on Power saver plan on battery at 0.8 GHz - the max CPU usage of Firefox varies between 24 to 27%. Obviously it is several times faster when the CPU is on 2.3 GHz than on 0.8 GHz, but it is always using maximum just a quarter of CPU power.

I wonder if Lenovo's Power Manager has anything to do with it, maybe it's just some bug somewhere?
Or maybe a bug in Firefox?