How the frequency / voltage curve works in Intel CPUs

[Islam Ghunym]

let's say I have a coffelake K sku chip in hand, and I want to enhance the maximum boosting clocks of 1 core 2 cores 3... by a different certain amount for each one of these. To do so gave a +offset vcore 0.1v to successfully go from (4.4, 4.3, 4.2, 4.1, 4.0, 3.9, 3.8) GHz to (5.1, 5.0, 5.0, 4.9, 4.8, 4.7, 4.7, 4.6) GHz.

 

What exactly happens to voltage curve here? does the offset apply across the whole curve starting from 100 MHz to the 5100 MHz reducing power efficiency in all situations? or it is smarter than that adding the offset only when core clocks goes beyond stock? which makes a lot more sense. Is there any way to any program that can draw the curve or something else that I can verify with it what is going on?

[DoctorNick]

2 hours ago, Islam Ghunym said:

let's say I have a coffelake K sku chip in hand, and I want to enhance the maximum boosting clocks of 1 core 2 cores 3... by a different certain amount for each one of these. To do so gave a +offset vcore 0.1v to successfully go from (4.4, 4.3, 4.2, 4.1, 4.0, 3.9, 3.8) GHz to (5.1, 5.0, 5.0, 4.9, 4.8, 4.7, 4.7, 4.6) GHz.

 

What exactly happens to voltage curve here? does the offset apply across the whole curve starting from 100 MHz to the 5100 MHz reducing power efficiency in all situations? or it is smarter than that adding the offset only when core clocks goes beyond stock? which makes a lot more sense. Is there any way to any program that can draw the curve or something else that I can verify with it what is going on?

Check out this thread, i'll answer your question: https://www.overclock.net/threads/offset-adaptive-voltage-core-i9-9900k-overlocking-question.1739276/

 

One tip when overclocking coffee lake is to apply the same OC across the board, for example:

9900K, boost table: https://en.wikichip.org/wiki/intel/core_i9/i9-9900k

Let's say you want 5ghz for all cores, then add 300mhz to every core in this table. If CPU isn't able to run 5.3ghz on core 1 and 2, you can lower this.

Applying the same OC to uncore, which by default is 43x (4300mhz), 4600mhz for this example. By doing this you allow the CPU to operate like it normally would. I used to run my 9700K like this and it worked very well. Also note that most boards have a CPU behavior (SVID behavior), that allow you to select CPU VID. Offset voltage will modify this. As far as I remember you should select adaptive or adaptive offset, for dynamic voltage to work, eco modes, speedstep etc. Also if you want uncore to follow this, and allow downclocking on idle, select Ring Down.

 

[Islam Ghunym]

On 5/13/2024 at 10:06 AM, DoctorNick said:

Check out this thread, i'll answer your question: https://www.overclock.net/threads/offset-adaptive-voltage-core-i9-9900k-overlocking-question.1739276/

 

One tip when overclocking coffee lake is to apply the same OC across the board, for example:

9900K, boost table: https://en.wikichip.org/wiki/intel/core_i9/i9-9900k

Let's say you want 5ghz for all cores, then add 300mhz to every core in this table. If CPU isn't able to run 5.3ghz on core 1 and 2, you can lower this.

Applying the same OC to uncore, which by default is 43x (4300mhz), 4600mhz for this example. By doing this you allow the CPU to operate like it normally would. I used to run my 9700K like this and it worked very well. Also note that most boards have a CPU behavior (SVID behavior), that allow you to select CPU VID. Offset voltage will modify this. As far as I remember you should select adaptive or adaptive offset, for dynamic voltage to work, eco modes, speedstep etc. Also if you want uncore to follow this, and allow downclocking on idle, select Ring Down.

 

Oh thanks for detailed info. However, I use a different approach when overclocking.

What I can take as an answer from your reply is that what I am looking for is the adaptive offset voltage, and that can be or not be there depending on the motherboard used for OC.

 

The adaptive offset applies the + offset only in boost mode, but does that mean it applies anywhere over base clock (2400 in my chip)? or the 8 cores boost (3900 in my chip)?

 

Edit: I looked up in my Gigabyte bios, and found that what I am using is what Gigabyte calls Dynamic vcore (DVID). looking further in the web I found some uncertain information claiming that it is the same as adaptive offset, and it works properly only when EIST and Enhanced Halt are enabled (which they are enabled for me). 

 

In the light of that, and because I am not sure when the + offset kicks in, I set the base clock to what was previously maximum boost clock before overclocking (4.4GHz) so the positive offset kicks in when clocks are higher than that hopefully saving some power.

 

Edit 2: Gigabyte's DVID seems to be just a normal +/- offset not smart or adaptive in anyway. It just adds additional voltage across the whole curve resulting in less multi core performance. I verified that using multi core benchmarks which with such a CPU at 45W shouldn't be reaching any high frequency over the stock, and yet the performance drop in the multi core scores is significant which means it is running at a higher vcore than stock reaching the power limit sooner and so lower clocks as a result during the benchmark