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Overclock-101

Wanted to know about overclocking?

It might looks old but it's not!
This post was written for LEVEL51 Laptop with 8th Gen Desktop CPU (Yes our Laptop USE DESKTOP CPU in some models) but the same principle still applies for all modern Intel Desktop/Laptop CPUs

As someone who has been using computer since 1990s and have tried almost everything from AMD and Intel (Cyrix included! but I doubted not many people would know about this CPU! - I can say that Intel offer more finely tuned overclock experience and there is a lot that can be adjusted.

Intel's program used for overclocking is called Intel XTU, (which you can download it from here. Also, you should read about why your CPU does not always run at Maximum Boost Clock, to get the base knowledge of what we are trying to do with overclocking 

For AMD fans who use Ryzen, I have been using Ryzen 7 1700x on my desktop PC as well, the program to use is call Ryzen Master. I have adjusted it to 3.9GHz with 1.35V voltage because if using at 3.5GHz default clock it felt really slow. However, there is not much to talk about in Ryzen Master (at the time of writing) - just clock and voltage and that's it. I have tried to reach 4.0GHz but that took 1.45V which is super scary for modern CPU.

What are we going to adjust for Overclocking?

For overclocking Intel CPUs, there are two related settings: Thermal and Clock Speed . These two are inevitably related because as the speed increases, the CPU will radiate more heat 

The LEVEL51 series NX , SX, is powered by the i7-8750H CPU, which is a non-overclockable CPU. We will only be able to fine-tune the Thermals but not Clock Speed. Althoguh, we could make it run at FASTER clock speed regardless.

As for our LEVEL51 Laptops that use Desktop CPUs, namely NXL or XL17, if you are using CPU that ends with K - you will be able to adjust both.

If you still haven't read this post before - I can tell you in brief that: Each CPU will have a specification about its heat that will be radiated from CPU when it is working called TDP. This value is used as reference point for system designers to design a cooling system that is capable of remove that amount of heat from your CPU. The reason why you can make your CPU runs cooler is because the heatsink/water cooling system that you have used is capable to remove more heat from CPU than its TDP value - just like you are using 25,000 BTU Air-con in a small room. 

Settings About the Heat Management Systems

Overclocking is like tuning a car, but the car may not be as good as the CPU because in the CPU chip nowadays there are many self-protection circuits in order to make it work as long as possible. with maximum efficiency.

And One of the most important variables is heat.

As mentioned before, Heatsinks are designed to support the cooling of the CPU according to the TDP specified, but another point that affects the cooling is. thermal conductor Or many people call silicone, TIM (Thermal Interface Material) , Thermal Grease, or Thermal Paste.

Of course, the people who designed our laptop at Clevo has designed the cooling system by taking into account the performance of the TIM that will be used too - as well as the cost and complexity to produce the laptop. One way to improve the efficiency of cooling system is just to replace this TIM with higher-performing ones. 

For LEVEL51, the most potent one we offer is LIQUID Pro, which is a pure metal TIM that require special care and treatment. You can find test results from the YouTube channel, Play3r TV (Click to open the video)

By using this high potency TIM - the CPU will be able to cool faster - allowing it to run at a higher higher speed for the same TDP Level. (Since the heat is removed faster, the heat level at CPU is lower) Or we can do the opposite by setting the laptop to run at higher TDP Levels

Well, it's time to Open Intel XTU and select All Controls under Advanced Tuning .

For the heat-related options, they are as follows.

Core Voltage Offset : The offset of voltage that will be supplied to CPU - which means that if the CPU chooses to use 1.0V, we will give it less. For example, if we set -0.050V, it means that if the CPU chooses 1.0V, it will use the value 0.95V instead.

The positive effect of reducing the Voltage Offset (meaning more negative: such as -0.1V) is less heat radiated from CPU - allowing it to run at LOWER heat Level

The negative effect of reducing the Voltage Offset is stability - it might be blue screen or just froze. How much you can reduce depend on each CPU sample that you have.

Turbo Boost Short Power Max : This is Power Limit 2 (PL2) - usually it will be set to 20-30% more than CPU TDP Value. Such as 81W for 65W TDP CPU. This value control maximum heat that will radiate from CPU at any given time - but NOT ALL THE TIME. It's for short burst only

The positive effect of increasing the PL2 is your CPU can boost higher during a short time window.

The negative effect of increasing the PL2 is there could be a short time that your CPU Temperature shoot up because your heatsink could not keep up with sudden surge in heat output.

Turbo Boost Power Max: This is Power Limit 1 (PL1), in other words, the TDP of the CPU itself. It is usually set to equal TDP. By design, the CPU should run at its base clock speed when it radiates heat equal to this TDP value.

The positive effect of increasing the PL1 is your CPU will run at higher clocks when CPU Load is 100%

The negative effect of increasing PL1 is your CPU will be hotter, remember that the heatsink was designed for a given TDP value - increasing the TDP beyond what heatsink was designed for - it won't be able to keep up.

Turbo Boost Power Time Window : This is quite confusing setting and very hard to see in practice, due to many factor affecting it. This is the time the CPU will try to maintain the PL1 level. Assuming that we set it for 8 seconds, within 8 seconds the heat from the CPU will not exceed PL1.

The disadvantage of reducing the  Turbo Boost Time Window is that the CPU will run at a higher TDP level than PL1 but less often than PL2.

Processor Core IccMax : By design, CPU will attempt to use higher voltage when its getting hotter to improve stability. So, as your CPU runs and gets hotter - it will begin to request higher and higher voltage, which it turn, also make it hotter! To ensure that the CPU will not stuck in this endless voltage increasing loop, you can use IccMax to control the maximum amount of electricity (Current) that CPU can draw. 

AVX Offset : The reduction of clock speed when  the AVX instruction set is used, which is a set of instructions to increase the efficiency of working with a large number of floating point numbers. It's a very power hungry instruction so the CPU needs to lower its clock speed to help. For example, if the CPU was running at 4.0GHz, if AVX Offset of 5 was set, it would run at 3.5GHz instead when AVX instructions is used.

The disadvantage of adding AVX Offset is that the CPU will run at a lower speed. When using the AVX instruction set

Let's get to know your CPU Status

For testing. t is recommended to use LinX. You can download it from many places. It is recommended to download from Softpedia website  .

Now go to Settings and adjust Priority Class to Idle first, because otherwise your laptop will appears frozen since Linx (Linpack) will use the CPU fully so much that there is no time left for us to process our clicks.

And before pressing the Start button, press All after Memory (MiB) to make it expand the Problem Size larger so it can run a little longer per cycle.

Here are the stats from the XTU screen captured from the  i7-8700K in the NXL with PL1 set to 45W times the i7-8750H and Turbo Boost Short Power Max off.

What does the graph and status tell us?

Power Limit Throttling in yellow is now displayed Yes, this tells us that Our CPUs are now radiate heat at PL1 level and we're getting Power Throttled.

Package TDP is the amount of heat that the CPU is releasing at the moment. You can see that it is 45W, equal to what we set in the value of PL1 (Turbo Boost Power Max). This includes all parts of the CPU, that is, if the GPU and Memory Unit is hard at work, it will also be included in Package TDP.

Max Core Frequency is the maximum speed from all cores that are currently running. Currently, Active Core Count is 6, which mean it is using all 6 cores on the i7-8700K and now it's running at just 3.0GHz. Almost the same as i7-8750H  Laptop with 6 Core Active.

Processor Cache Frequency is the speed of Cache or high-speed memory on the CPU. This is the speed of L3 Cache. Normally, L1, L2 should be running at the same speed as Core speed. If you enjoyed reading our post, I recommend you read about Cache/Memory Coherency as well too. And you will understand why there is Xeon/Opteron CPUs.

Current Limit Throttling Whether the CPU was Current Throttled

Intel Datasheet has specification on the absolute maximum current which CPU can cope with and it is 138A for 6-8 Core CPUs. You will see this, if your cooling solution is TOO GOOD - and there is nothing you can do. You could increase Process Core IccMax, but that is not recommended!!!

The reason you get Current Limit Throttling is because Temperature is Low so the CPU never get to the PL1/PL2 level so it can boost freely until it hit its maximum boost clock specified by you or by Intel. As it runs faster, it draws more current and that is why there is this Current Limit to prevent CPU from killing itself by drawing too much electron through itself. (YES, COLD could KILL your CPU Too!!)

Mainboard VR Thermal Throttling and Thermal Throttling are two things to avoid. The first one means our power supply circuit on the mainboard (VR = Voltage Regulator) is too hot - becasue it is supplying a lot of current to the CPU. Thermal throttling means your CPU already running at TJMax (T Junction Maximum) - the point just be fore the things in CPU will actually melts.

Package Temperature is temperature of the overall CPU Package, which includes its GPU and also Memory Controller.

The word throttling generally means that The speed of the CPU is being controlled (Throttle) for various reasons described above.

We can also press the wrench symbol to show more status, let's also addCore Voltage for next excercise.

How PL1/PL2 and Core Voltage Offset Affect Clock Speed

To get better understanding of PL1/PL2 and all this Turbo Boosting stuff, lets try this:

  • Turbo Boost Power Max : 45W
  • Turbo Boost Power Time Window : 4s
  • AVX Offset : 0

Then open LinX and set it to work for abit until Power Limit Throttling Lit up. Then try to increase the Turbo Boost Power Max to 50, you will see a minor speed increase - in my case it goes from 2.95GHz to about 3.1GHz.

At Turbo Boost Power Max = 80, the CPU is now running at 3.77GHz

Noticed that there will be some periods where there is no Power Limit Throttling and the heat is reduced as well, even though the utilization is at 100% This is when AVX code in LinX is not running. You will see that without AVX Code, CPU could go up to 4.29GHz while the Package TDP is just 73W!

Now let's see the effect of Voltage Offset. This could crash your laptop/PC so pleae save your work first! Note that you need to REDUCE the offset - that means it must have Negative Sign in front of the values. Let's try setting Voltage offset to -0.1000V

It can be seen that when the Voltage Offset is set to -0.100V, the speed increases from 3.77GHz to 4.08GHz (an increase of 8%) . You could try to give it more offset, each time by 0.025V increments, for example

  • -0.1000V to -0.1250V
  • -0.1250V to -0.1500V
  • -0.1500V to -0.1750V

At -0.125V, Clock Speed increases from 3.77GHz to 4.17 GHz already (10% increase).

At -0.1500V, we get 4.23 GHz (12% increase)

But for this CPU, it is not stable at -0.1500V and then a Blue Screen occurs.

As you can see, the Clock speed of CPU came from multitude of factors - but the most important thing is the Heat Output. If you want more Clock Speed, just try to keep your CPU Cooler.

Of course, it would be more challenging for most Laptops since the cooling space is limited and it was designed to run at a specific TDP value. So you could get better clock speed by using Voltage Offset as well as using better TIM as we did.

Adjust the speed with a multiplier

"Overclocking" these days is actually just adjusting this "multiplier". Do not forget that usually the CPU that we use today came with Automatic Overclock system already - which is the Turbo Boost. For example, i7-8700K's base Clock is 3.7GHz and the Boost Clock is 4.7GHz. Here we are just going to allow it to overclock even more.

The settings are in XTU, right here.

You can see that while it is advertised that boost clock is 4.7GHz, in reality if you are using all 6 cores - the clock would be at 4.3GHz Maximum (43x = 43 x 100 = 4300, 100MHz is the system clock speed)

For a machine that is a CPU that does not have a K code, of course, it cannot be adjusted. And if you are using K CPU with H-Series motherboard (not Z series) - you will not be able to change this value as well.

The best settings is just let CPU runs at 1 Core Boost Speed even though all cores are active, like this:

This settings means that, the CPU will try to reach 4.7GHz when:

  • Package Power does not exceed Turbo Boost Short Power Max/Turbo Boost Power Max
  • Processor IccMax is not reached
  • Temperature does not reach T Junction

From our Test Laptop (with i7-8700K installed) we can see that it can reach 4.69GHz at the beginning while it's not very hot and AVX Code is not active

and when we let it run, will see that the speed comes to a stop at 4.1GHz

Conclusion

I hope you enjoy reading this article and got some idea about how PL1/PL2/IccMax are related and we might have given you some ideas how to squeeze out more Clock Speed from Your Laptop.

By the way, you dont have to try so hard and just select our LEVEL51 Laptops which are already capable of running faster than "normal" laptops. i7 in our MB 2021 Model Year is actually faster than Ryzen 9 and almost as fast as i7-11700K Desktop CPU!!!

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