VPC-Z2 owners - battery cpu throttling?

I leave my Z2 power profile set to balanced, and today I noticed some monster spreadsheets took 2-3x as long to open as when I am plugged in.

So I did some digging around. the "balanced" setting has 100% set for max cpu state (windows setting)- yet the computer is much slower than it is when it is set to "high performance".

Then I tried geekbench. On the "balanced" setting - I get between 3000-4000...and on high performance I get around 7000 (I have the i7).

All these tests the Vaio thermal strategy was set to performance.

So....what software is doing this and why?

 

OK so I did some more testing (using throttlestop, prime95 and some others)...what's happening isn't throttling, but a delay in the cpu speed ramping (governor)?

On high performance, when I start prime95 the cpu ratchets up from 900mhz to 3.2ghz instantly.

On balanced it's a stepped ramp up to 3.2 and takes about 8-10 seconds...very interesting.

 

In balanced mode I suppose the system takes time (and resources) to detect changes in system load and respond suitably over several iterations.

Laptop designers do a lot of things to reduce power consumption when running on battery. A few years ago, when HD movies were a challenge for most hardware, I noticed that videos that played fine when running on mains power would stutter on battery power.