[Galaxy Note 3 Q&A, Help & Troubleshooting] nicholaschum:
I can give you a brief (easy) explanation with comparisons to try to get you to understand what a kernel is.

A kernel is your phone's

driver

(like a car) where it adjusts settings of the hardware and controls how each individual part interacts with each other.

There is a reason you take a car to get tuned up, and that is because a car can go berserk as there is no "maintaining force" - YOU or the person who tunes your car makes changes to the car to make sure it does not overheat, use less power per mile travelled, control how much windshield fluid is being released or how much torque force required to ensure the car does not snap XXXXXX when going at a speed of YYYYYY.

These options are beyond the manufacturer's decisions, and therefore when people flash a kernel you immediately trip KNOX (N9005). You can give your phone less power to process, more power to process (not recommended), speed up the CPU/limit the CPU, control governors on how the disk I/O (input/output) is being handled and/or control how much the phone will swap to it's virtual memory when it reaches no memory.

People think use a custom kernel! It saves you a ton of battery life!. This statement is partially wrong. You have to understand how a kernel reacts to your phone. Even though I know that lite kernels like Wootever's Custom N3 has the best battery life, this is because it has less tweaks and features that may boggle the user, and may allow for subsequent battery life extension compared to CivZ's SneakyKat or Imoseyon's LeanKernel. By inserting new tweaks into the kernel, you allow to have more "useful" features that may add to the "driver's knowledge" - Color tweaking, Fast charge over USB, CIFS support, all are extras that the kernel supports. To save power, developers remove the junk that the manufacturers added and added their own settings to make sure they get the result they would like, then they would share it to the public. However, people recommend custom kernels as they get more options when they flash it, as well as ridding of a lot of the stock settings that manufacturers love setting (default governors, lowest CPU frequency, etc)

CPU governors work by controlling how much speed is used at a given time, a good description of what each governor does is listed here: http://xdaforums.com/showthread.php?t=1736168

I/O governors (simply speaking) control how files and requests are being handled by the system, a good description of what each governors is listed here: http://xdaforums.com/showpost.php?p=23616564&postcount=4. Good way to understand this is if you learnt programming and you learnt the Stack/Queue ADTs in a programming language, it describes things better when looking at the descriptions in the link above.

Adjusting Synapse/Trickster would not get you anywhere to getting the best battery/best performance out of the phone. You will have to experiment and check which kernel is best with your phone, according to your

SOC_PVS value

. SOC_PVS value is how Qualcomm decides your processor's manufacturing "rank" and if you compare a low rank to a high rank, you will see that you can use less power to operate a high ranked chip compared to a low ranked counterpart. As most governors rely heavily on how the code is handled by the system, you should always go for the kernel that fits your system, and setting configurations depending on your system's likings. By following other people's configurations you risk sporadic reboots and incompatibilities, as not all phones are built the same way.

Things you should not touch if you are afraid of destroying your phone: Overvolting and Overclocking, as these may fry your device if you don't know what you are doing.

Any questions - click reply to this, or else I won't see it!