Why is Intel Turbo Boost Not Working On My Laptop?

Solution 1:

Latest generation Intel processors automatically under clocks your processor in order to save energy when you are not using it. Seeing "Energy Saver" listed under the monitor program is nothing to worry about.

From Intel:

Turbo Boost -

Intel Turbo Boost Technology 2.0 is activated when the Operating System (OS) requests the highest processor performance state (P0).

The maximum frequency of Intel Turbo Boost Technology 2.0 is dependent on the number of active cores. The amount of time the processor spends in the Intel Turbo Boost Technology 2.0 state depends on the workload and operating environment.

Speed Step -

Enhanced Intel SpeedStep® Technology

Enhanced Intel SpeedStep® Technology is an advanced means of enabling very high performance while also meeting the power-conservation needs of mobile systems. Conventional Intel SpeedStep Technology switches both voltage and frequency in tandem between high and low levels in response to processor load

From what I can tell and have seen, these two technologies are highly linked. Turbo Boost is a feature that has come from Speed Step (that has been available for a long time) and enabling Turbo Boost requires Speed Step to be active.

I would say that your BIOS is lying to you and it should disable the ability for Turbo Boost to be changed whilst Speed Step is disabled. From looking at some of the laptops I have on my bench, Speed Step can not even be disabled - it is a good feature that can increase the battery life quite a bit and I am not sure why you would want it disabled.

Also, if you really want to update, go to the official Dell site, type in your asset code and download the latest BIOS/EFI Updates and chipset drivers. I think the BIOS/EFI has the best chance here but, it never hurts to update the chipset drivers either.

Solution 2:

1. Make sure you've got all devices installed in Device Manager
2. Make sure you're updating your Dell from Dell's website (which also uses your Service Tag to be able to find the right drivers for your model). Most of the devices in driver pack you linked in your questions are older then the ones you get by directly downloading and installing your updates.
3. Try updating your BIOS. There were lots of fixes in A05 version for E6420 (which I do have as well with I7 processor and it seems to work just fine. )

1. Added support for Signed Firmware Updates.
2. Additional vPro support. Added DASH ‘PLDM for BIOS Control and Configuration?
3. Updated the Password Bypass feature.
4. Fixed issue where the system would not reboot the first time after disabling the Integrated NIC in Setup.
5. Addressed issues with the 'Auto-On Time' Setup field.
6. Fixed issue where a UEFI OS install would fail with greater than 8GB of memory.
7. Addressed intermittent boot issues in ATA mode.
8. Fixed issue in ATA mode where unaligned memory accesses would fail.
9. Fixed issue where the BIOS would reboot instead of flashing when the /S parameter was used with the flash executable.
10. Fixed issue where the error log data from the previous POST would show up if you shut down the machine at the F1/F2 prompt.
11. Fixed issue where the IDT audio device would not appear in device manager when running a UEFI OS.
12. Updated to the MOB_P_08 version of the Intel microcode patch.
13. Updated to the 1.3.72 version of the Intel PXE OROM.
14. Updated to the 4208 version of ePSA diagnostics

EDIT: Consider updating to newest BIOS A08

Changes are:

Fixes/Enhancements
1. Fixed issue where Intel Turbo boost non-functional. (sound familiar?)
2. Fixed issue where TDM PBA SSO doesn't work when both FP and TDM PBA SSO are set for single user. 
3. Addressed some keyboard with USB Hub not accessible during POST.
4. Updated to the 1.4.0 version of Intel PPM Reference Code. 
5. Updated to the MOB_P_13 version of the Intel microcode patch. 
6. Intel Trusted Execution Technology updates 
7. Updated to the 1.05 version of Dell GPE. 
8. Added new key for Signed Firmware Updates. 

Note: 1. Please note that if the A04 or before A04 BIOS is currently installed on your system, you must first update to A05 BIOS and then flash to the latest A-rev BIOS.

Solution 3:

Try plugging in your computer. My turbo boost only works when my computer is charging. I think that the default settings disable it when its not charging. It saves power. Turbo boosting is so nice for games though, try to always play while charging!