This guide is intended to help those who are coming to the Kernel KT747 by @ktoonsez. This thread and the subsequent Posts are intended to be as a Guide for users that are new to this Kernel and its Tweaker. Complete credit for the development of the Kernel goes to @ktoonsez. You can find his Kernel thread bellow.
KT747 - SGH-T999 Touchwiz & AOSP - Thread by Ktoonsez
Older Builds of the Kernel - Thread by @LuigiBull23
There are quiet a few times when users have asked for the choice, usage as well as definition of various parameters of the Governers and Schedulers. Hence I decided to write this guide as a way to help the users understand the various basic terms and parameters. I am perfectly aware that there are quiet a few excellent guides on the different ICS & JB Governers. As a matter of fact, I have linked to some of them. So eventhough I have given basic information on Governers in this kernel, it is not my primary purpose to serve this as the ultimate guide on that subject.
This is a living guide and given vastness of the subject, I will continue to modify the OP as well as subsequent posts.
I am not responsible if you end up with expensive brick. Read the guide as much as you want and ask questions before proceeding with overclocking.
Overclocking and undervolting is highly debatable, some say its good and some say its bad... so its upto you to proceed further. While on the word of Caution – I have personally managed to Smoke (I mean literally physically cause smoke) from a Tablet by testing SetCPU Overclocking on it.
Here’s another nice detail on why Friends don't let Friends do extreme Overclock or Undervolt! post by @dorimanx, the developer of the other excellent kernel.
PURPOSE / INTENT -
The intent of this thread is to help new users learn, and act as reference for more knowledgeable users, on the Governers & Schedulers incorporated into this Kernel. Another Purpose is to help those who are new to Overclocking & undervolting in general.
There are quite a few good guides on this forum regarding Overclocking. So Rather than writing one myself, I am going to refer to one by @bala_gamer, who has written a pretty comprehensive guide for the International version of Galaxy SIII. Even though the hardware is different between that phone and this one, the guide is good enough for those who are starting down this path and want to get basic understanding.
Another intentional purpose of this thread is to provide a platform to discuss Overclocking and undervolting settings for SGH-T999 specific version. Given that I wish offer to the experts a platform to discuss, in interest of New users and their phone, I have been careful enough to include warnings and footnotes where possible.
WHAT DO I GET BY OVERCLOCKING/UNDERVOLTING -
In short, modern Microprocessors, to a certain degree have a range of Operational frequency steps. Also especially for multiprocessor devices, it is possible to control when a processor comes into play and when it does not. Now, the main question that comes to mind is, why would you want to turn off processors? Well, consider this. It’s Kind of an analogy like a car engine. On a 6 Cylinder engine, the fuel consumption is a lot more. But if you were to turn off 2 out of the 6 cylinders, then there is still power to drive and fuel consumption is lower. Similarly, with one of the processor turned off, battery drain is reduced not to mention heat generation.
For a given processor, by design the higher the frequency it operates, the more raw power you have available to run applications. Typically on some of the previous generation single processor phones, its not possible to run Angry Birds or other games unless you run the processor consistently at its maximum operating frequency. So users may choose to Overclock the phone in order to run such Apps.
On the flip side, if you are a light user, then it will benefit if you turned off the other processor(s). This saves the battery. Given there are multitudes of Frequency steps, if the processor operates at lower frequency, there is less heat generated and less battery used. Before I proceed further, I am respectfully Quoting Castle_Bravo from here. He has summarized perfectly what I’d have said otherwise.
In the pc world we have things like clock speeds, latency, read speed, bus speeds and things of this nature. Right now im going to talk about over clocking a processor, whether it's a gpu I or a cpu. When we over clock these devices, meaning make them go faster than originally rated by the manufacturer using software of any kind, these devices will also work harder. The faster the clock speed the hotter the component gets and the shorter it's life span is due to thermal stresses. Hence our manufacturer rating of speeds.
There are two ways to combat heat; heat is the main enemy in any high powered system (do a YouTube search of running a cpu with no heart sink). Add more cooling via more hardware and lower voltages applied to the component. Adding more cooling hardware is the preferred method. This is the best way because now that the component is working faster at the same temperatures it was at before on stock clock speeds it is, in terms of math, working LESS. This applies to ram, video card, cpu's and the like.
Typically, as you raise clock speeds you also have to RAISE voltages in order to keep it stable. There are exceptions like in a VERY minor over clock you can actually lower voltages. The trade off here is that with the larger cooling equipment and the faster clock speeds the processor will spend less time at peak load and return to idle faster. If set up correctly you can actually draw less cumulative power using higher voltages. This is assuming temperatures are the same for both scenarios of stock clock and over clock. BUT, more power applied equals more heat. Now, as we raise clock speeds and raise our voltage, we try to be on the edge of not enough. Because what does more power mean? More heat. And what does more heat mean? Less component life. Not only that but the components have a "healthy" voltage band due to tolerances in its manufacture so we don't want to exceed that.
We undervolt mainly to protect the equipment. Secondary is battery savings. We do not have the option of installing more hardware to cool our devices so all we can do is lower voltages. Lowering voltages will help keep the component cool because it is pulling less electrons. More power = more heat. the cpu will become unstable and make it work harder, which is counter productive and will have a reverse effect. So take that voltage too far down and now the component doesn't have enough power to perform its job properly or efficiently, making it work HARDER. What happens when a component works harder? It heats up. So we can actually have a reverse effect from our intended power savings.