It's looks old but it's not!
While the content is about Intel 8th Generation (it's when we experience the first instance of this "issue") all the information in this post still applies to all modern CPUs from both Intel and AMD. So, read on!
Regarding Turbo Boost, this is quite a headache, because in the media we often see impressive numbers, for example, the i7-8750H has a maximum speed of 4.1GHz or the i7-8550U has a 4.0 speed. GHz - Low Power Ultrabook is almost as fast as a big Laptops for even PC!.
But if you ever try to open Intel's website, for example, the model i7-8750H, we will see a message written like this:
What does it mean? If summarized in a language that is easy to understand is that it will work at 4.1GHz in the case of a Single Core being used, which is in fact - almost never happened.
It must be understood that we have reached a dead end in CPU speed technology for quite some time now.
From the pictures (click on the image to view the original research) you can see that there was a period of time when CPU speed increased dramatically, almost linearly. (10^2 = 100 MHz, 10^3 = 1GHz) and then stops at about 4,000-5000 (4-5GHz) that we see today.
The reason is because the higher the speed, the more electricity, or more electrons, run into the CPU's circuitry in the same amount of time.
Some of these electrons had to be trapped by switches that made up a processing circuit known as transistors (now CMOS) - which generates heat. Also within the circuit there is resistance (R) which generates heat, too.
In fact, we can make the CPU run faster. However, it will be too hot and it won't be making any sense to use in practice because you will have to rely on very hefty cooling to make it work. Not to mention the amount of electricity bill!
First of all, we need to know about TDP.
The picture below is an example of a CPU i7-8700K running at a speed of 4.7GHz, which is the Turbo Boost speed of the i7-8700K that Intel said by using the program ThrottleStop to run the test which use all 6 cores at the same time - Or 100% Load.
Note two important values involved, Voltage and Package TDP (Power in the ThrottleStop screen) that say Votage is now 1.24 Volts, and Package TDP (Power) is 114.6 (W).Y es, and in the middle right corner of the picture you will see that the CPU now finds a yellow "Power Limit Throtting" as well.
If you try to open Intel's website, you can see that Intel's Base Frequency or normal speed of the i7-8700K is set at 3.7GHz and Max Turbo is 4.7GHz and The TDP is at 95W .
So, I have tried to get the i7-8700K to run at 4.7GHz on all 6 Cores, the TDP even exceeds the value Intel set by 20%~ Plus, it still doesn't work at the speed of 4.7GHz that is set up as well (just 4.5)
So what exactly is TDP?
Intel says it like this: "TDP (Thermal Design Power) is power in watts. that the CPU will radiate out When running at Base Frequency, when all cores are processed in a very complex computational task that Intel has put in place (to measure this).”
In conclusion, TDP is the amount of heat that the CPU will radiate when every Core is running at the Base Clock speed , which is 3.7GHz in the case of the i7-8700K . And at its Max Turbo speed, which is a 27% increase from the Base Clock, also generate ~20% more heat (from 95W to 116W).
So why is there a Turbo Boost? What is it?
As previously mentioned, we have reached a point where we cannot speed up the CPU without overheating it anymore, so when Scale-Up (faster) can't be done, Intel has nothing to sell to us. We all bought a new CPU We hope it will be faster, right?
So Intel engineers have to start Scale-Out, What they did is they took two CPUs and put them next to each other and let it work together as if we had 2 CPUs in a single CPU slot. The first Intel Chip that has 2 CPU in One (which is the world's first For Desktop) is two Pentium 4 into the same CPU, becoming a Pentium 8, oops, Pentium D. By itself, Pentium 4 is a very hot chip, putting 2 together have maxxed out TDP at 130W.
See how they put 2 CPU together in a rare photo from Techarp.com .
This event made AMD look very good at the time - because the AMD Athlon 64x2 are better architected and designed since it was meant to be a Dual Core, from the beginning. It's not until Intel's Conroe (the middle picture above is the Core 2 Duo version) that they properly do a true Dual-Core design
The CPU having more than 1 Core causes new problems for everyone - some of which are:
- Most programs in the beginning (And now too) has not been written to use multiple cores simultaneously (program is a single-thread) because doing multiple threads will make the program more complicated. It used to be a free lunch period for programmers when new CPU automatically make all programs run faster - the introduction of Multi-Core CPU put an end to it because the CPU does not run faster, it just has more Cores in it.
- If there is a Single Thread program running, one heavy program, such as opening a game , the other Core is mostly idle, rarely doing anything, may be a background task, such as scanning for viruses, receiving ICQ messages, MSN (in those days)
- If the CPU is a Dual Core, the budget TDP must be divided in half. It is TDP 130W. Actually, it is 65 + 65 = 130 or TDP 95W = 47.5 + 47.5. That is: one CPU Core (in the dual Core CPU) is limited to use only HALF of the TDP available
And if anyone catches up with Pentium D 805 - you will know that it Overclocks a lot - 3.5GHz comfortably from 2.66Ghz. and everyone gets one and overclocks them like crazy. But actually, I think we missed the point - Pentium D805 doesn't Overclock a lot - The CPU Already capable of going 3.5GHz per Core - it's just cannot do it when both cores are active - so Intel has to limit them to 2.66GHz!!! (There is no "Turbo" in Pentium D era)
So that is why we require Turbo Boost. The idea is simple - if the TDP of the whole chip (Package) is still not met with the Quota and at that time the heat is not too high, automatically overclock only the Core that is being used until the TDP quota is met!
If we want the 8750H CPU to run 4.1GHz all the time, is that Possible?
You have to look first and see if there are any variables. Related to Turbo Boost, some .... there is only TDP only, which is if the current TDP is not exceeded , it will automatically Overclock.
Now, next, we have to see that What affects TDP?
We already know that the main thing is the speed (Clock Speed). The higher the Clock Speed, the hotter it gets, the hotter the TDP number is higher?
You can see from the following taken from our older model XM15 (New model from LEVEL51 which use Desktop CPU is XL or NXL) can see that now the speed is up to 4.7GHz as I have already set and TDP is reduced from 116W to 97W!!! HOW??!!?
Faster but emit less heat How is this possible? You Must look at the Voltage which can see that from the previous picture, the Voltage is at 1.2404V , but in this picture the Voltage is reduced to 1.1184V , decreased by 0.122V , or about 10%.
It appears that we reduce the Voltage by 10 % resulted in a 16% drop in TDP - or we can conclude that If we reduce the voltage - the heat released (Package TDP) is also reduced. Which trigger the Turbo Boost system to run CPU at a higher speed.
If you look at the picture, you will see that it is written that Core Voltage Offset is written -0.125V. What I'm doing here is called Undervolt .
OK, then can we get i7-8750H to runs 4.1GHz all the time even with 100% Load? Can we just put the laptop in snow strom to make it happen?!
The answer is that it's still no >.<
Why can't the 8750H run 4.1GHz all the time!? :'(
That's because the CPU 8750H is a CPU that is "Locked Multiplier" because it is a model that can't be overclocked. For the "Unlocked Multiplier" it will be a model with a name ending in K, such as 8700K
If you ask why the 8750H has to be a speed limited? While the chip is almost an exact same chip as i9 or higher-end model. Intel has tested that this chip is still not capable of going high speed stably. So they limit the speed, disable the cores and sell it as i7-8750H instead of 8850H or i9
This process is common. For example, GTX1050 and GTX1050Ti are the same chip. The partially-broken GTX1050Ti is sold as GTX1050 instead of having to be discarded. Furthermore, GTX1080Ti is also a Titan Xp that loses some parts as well.
This process is called Binning Process . Because newer chips are bigger and more complex to produce, sometimes part of the chip came out broken - but Intel would not throw away a partially functioning chip which can be sell for some money right?
Looking back you will see that we use the term "Automatic Overclocking" - so what is actually "Overlocking" nowadays means we adjust the Maximum Limit of the Chip - not adjust its running speed. It doesn't guarantee that it will work at the speed we adjusted
For example, the 8700K that I gave an example - works at a speed of 4.5GHz while multiplier was set at 4.7GHz, etc because the yellow Power Limit is Lit up
For the i7-8750H Intel will not specify the speed or Maximum Boost of each Core on the web. (I remember seeing But I can't find it on the Intel web as well), but we can go and see it on the web. or open the Intel Extreme Tuning Utility program.
For the 8750H the settings are as follows:
- - 6 Core : 3.9 GHz
- - 4 Core : 4.0 GHz
- - 1-2 Core : 4.1 GHz
The 7700HQ is set as follows:
- - 3-4 Core : 3.4GHz
- - 2 Core : 3.6 GHz
- - 1 Core: 3.8GHz
If you just look at the numbers We would feel that - in addition to going from 4 to 6 Core, the 8750H can also be faster while still has the same heat dissipation (TDP) at 45W!
Points to note from the results of this test:
- i7-8750H (TDP 45W ) most speeds are around 3.0 - 3.2GHz from the 3.9-4GHz set by it's Power Limit. On a side note, the base clock is 2.2 GHZ - going up 45% to 3GHz is already impressive.
- The standard i7-8700 TDP is set to 65W , it will speed in the range of about 3.6-3.7GHz or more.
- i7-8700 , when changing TDP to 95W (equal to 8700K), can do speeds in the 3.9 GHz level and up to about 4.2GHz
In short, the 8750H can't achieve 4.1GHz all the time, or even 3.9GHz all the time, for two reasons:
- Intel has already locked the Turbo Boost settings, which cannot be modified. That is, even though the CPU is running with great cooling, the maximum speed when 6 Core is limited to 3.9GHz.
- The 8750H's TDP is too low to allow it to run at such high speeds, which means at just 3.2GHz is already 45W.
But if compared to 7th Gen, in 7th Gen Intel will set the multiplier to fit the TDP, that is, the i7-7700HQ if running 4 Core at 3.4GHz, it will emit 45W of heat exactly, but in 8th Gen Intel has set The maximum speed the chip can reach, ignoring the TDP for us~ (Yay)
This is why the 8th Gen is so hot and the MacBook Pro i9 Throttle was so heavy before it was fixed , because in the MacBook Pro i9 BIOS it didn't change the value. TDP Limit, but leave it at 100W, causing it to overheat and overloaded the power supply designed for 45W CPU and begin the Throttle Loop - because it has never been the case that the multiplier that Intel set is higher than TDP before.
Another possibility is that Intel may be very cautious by advertising a low Base Clock before (say 2.2GHz, although most of them see it at 3.0-3.2GHz all the time) or it is possible that the quality of the chip is very wide range - they might expect the chip to perform poorly than expected - that is running hotter than currently is because it require higher voltage.
There may be some chips that it almost doesn't Boost up at all - that is it requires higher voltage than usual, causing it to reach the TDP faster than other.
In the other hand, we've also seen that there is a group of NXL i7-8700 that can do 4.3GHz speed all the time (Max Boost for 6 Core ) without having to adjust anything There is also a term for this event. That is, the customer won the Silicon Lottery
So, can we have a way to make it faster than 3.2GHz?
If you've read this far, you've probably already figured it out.
What do we have to do? :) There are two settings that we have to adjust: TDP and the voltage that we will supply to the CPU. Let me formulate the term. Let's call it Power Limit Tuning~
The way to adjust the TDP and voltage is not difficult at all. For all 8th Generation LEVEL51 machines in our current BIOS. All Overclock functions are unlocked from the factory (Yay). For other brands, I haven't had a chance to try. Can't confirm if it's adjustable or not. And this is my Power Limit Tuning work.
If you're lucky some of our NX machine has a speed of 3.89GHz with zero adjustment - that is because NX model has an overkill cooling for the CPU already.
- Now everyone will have to ask, So what needs to be adjusted? In detail, allow me to separate it into another post. Because it is related to overclocking too. Follow up on this post.