XPS 15 9550 update killed battery life?

I have been getting 5-7 hours of life out of my XPS 15 since I bought it in March. That is, until earlier this week when something happened and my battery life went to < 3 hours. The laptop has gone from being useful at work and evening off the charger to a computer that is required to be near an outlet. Has anyone else seen this recently (this week)?

One thing that I noticed is that now my system Idle CPU % is between 18-25% and the fans are running 30+% all of the time, where they used to run minimum speed most of the time.
I have attached a screenshot of CPU just a bit after boot up, you can see the high kernel/system usage and the overall system %.

Top running processes:
System - 3-8%
Antimalware Service Executable - 3-5%
Wmi Provider Host - 2-4%
Desktop Window Manager - 1-4%

Recent windows updates:
Update for Adobe Flash Player ... KB3189031 (9/2/16) - Happened post issue
Cumulative Update for Windows 10 Version 1607 ... KB3176938 (8/31/16) - Tried uninstall/install
Update for Windows 10 Version 1607 ... KB3176936 (8/23/16)

System specs:
XPS 15 / i7 / 4k / 16gb / 1TB / 84 whr
Bios: 1.02.00 (hasn't been updated)

 

Things I have tried so far, none have fixed the issue:

All fixes here:
http://news.softpedia.com/news/windows-10-high-cpu-usage-fix-490908.shtml

Just now trying DEP, that's what I traced the WMI Provider Host process to (using Process Explorer from MS):
http://www.online-tech-tips.com/windows-xp/disable-turn-off-dep-windows/

This save a % or so on the overall usage...
http://unsolicitedbutoffered.blogspot.com/2015/05/quick-fix-ms-office-click-to-run-and.html

Maybe try these next?
Wasn't able to find win10 version of this tool except in the ADK which was 6.7GB to install
http://helpdeskgeek.com/windows-7/fix-nt-kernel-system-process-cpu-usage-in-windows-7/

 

After downgrading the Nvidia drivers to 372.54 and upgrading the bios to 1.02.10 I have my CPU usage back to single digit % and battery life seemingly back to normal. I also uninstalled the prey app that I had to track my laptop, but I don't think that did much. Unfortunately this has also led to the screen flicker I have seen others talk about with this laptop.

I have no desire to go to 1.02.13 and end up with the 60% battery issues so I am going to live with it now until Nvidia and Dell release some newer updates.

 

Unforutnately, this isn't fully up and working yet, I found using my laptop this weekend for some CPU intensive tasks, my CPU is currently limited in speed to under 1 GHz. It only ever goes to 30% CPU, so it is VERY slow. This must be something in the firmware, any ideas?