Some questions on CPU OC and what actually happens...

[Gonio]

Hi all, I am no pro OCer, but understand most of the basics (I think), and how to do it. But there are a few things I don't understand yet or what happens actually when OCing. Feel free to correct me if I say something crazy

 

1A: Baseclock vs Multiplier. Multiplier is most used these days, and overall it is advised to go with multiplier over baseclock because of affecting the speeds of other parts like RAM and PCIe clocks, but a difference for Skylake is that it has become more viable again to use baseclock since most is now seperate from the CPU baseclock. To what I know and hear it gives more flexibility to OC. But flexibility on what? Is it only a extra method of achieving a certain speed instead with multiplier, or is there more to it like more precise or higher finetuning or other reasons?

 

1B: Maybe by the answers of 1A I can answer 1B myself, but just in case: Why would you want to use baseclock over only multiplier or vice versa?

 

2A: With GPU OC you overall hold your option for turbo since you can adjust baseclock if I remember correctly and boost limit scales along (on cards with turbo obviously). This doesn't happen with CPU if I am correct, or is this on newer platforms different? With my own OCed CPU the value given is the max of multiplier settings in my case, so that looks like there is no more turboboost. Or is that somewhat countered by the adaptive power settings and creating a similar turbo boost idea? or has that nothing to do with it all?

 

2B: Is this similar and also applying for AMD platforms?

 

3: I run a 3930k on Z79 platform at 4.0 Ghz. What are some noteworthy changes in options and possibilty since that platform and for example Skylake or possible Kabylake if that info is out there? Ofcourse the baseclock OCing making a comeback as mentioned by 1A. Any other things that are handy to know?

 

Thx for the input, and sorry for any typo's, no native English speaking.

[Guest]

multiplier overclocking has become more popular because the many of the benefits from increasing bus speed have diminished due to the newer layouts of the motherboard. 

 

I like to turn turbo off and have my CPU running my OC 100% the time. If you are concerned with power consumption, then maybe look at using turbo to your advantage. 

 

 

[Mira Yurizaki]

49 minutes ago, Gonio said:

1A: Baseclock vs Multiplier. Multiplier is most used these days, and overall it is advised to go with multiplier over baseclock because of affecting the speeds of other parts like RAM and PCIe clocks, but a difference for Skylake is that it has become more viable again to use baseclock since most is now seperate from the CPU baseclock. To what I know and hear it gives more flexibility to OC. But flexibility on what? Is it only a extra method of achieving a certain speed instead with multiplier, or is there more to it like more precise or higher finetuning or other reasons?

I haven't looked into this in detail but from http://www.anandtech.com/show/10021/skylake-overclocking-regular-cpu-bclk-overclocking-is-being-removed it appears that the DMI/PCIe clock domains were separated from the main CPU domain. However, this doesn't separate the memory controller from the CPU clock domain. So while you can probably push a Skylake CPU harder via BCLK alone, it probably won't be that much harder.

 

49 minutes ago, Gonio said:

1B: Maybe by the answers of 1A I can answer 1B myself, but just in case: Why would you want to use baseclock over only multiplier or vice versa?

BCLK is useful for making finer adjustments. Every time you touch the multiplier, you increase the clock speed by BCLK amounts.

 

49 minutes ago, Gonio said:

2A: With GPU OC you overall hold your option for turbo since you can adjust baseclock if I remember correctly and boost limit scales along (on cards with turbo obviously). This doesn't happen with CPU if I am correct, or is this on newer platforms different? With my own OCed CPU the value given is the max of multiplier settings in my case, so that looks like there is no more turboboost. Or is that somewhat countered by the adaptive power settings and creating a similar turbo boost idea? or has that nothing to do with it all?

I think the concept of turbo boost once you have a good enough cooler goes out the window. Turbo boost is meant to pump up the cock speeds of fewer cores if the workload is high enough and the thermals allow for it. If you have a good enough cooler in that all of the cores can be in turbo boost all the time, then that idea is moot.

 

So you can basically think of overclocking as increasing the range at which your processor can run at. Adaptive power settings will still adjust the multiplier as needed.

 

49 minutes ago, Gonio said:

2B: Is this similar and also applying for AMD platforms?

Yup.

49 minutes ago, Gonio said:

3: I run a 3930k on Z79 platform at 4.0 Ghz. What are some noteworthy changes in options and possibilty since that platform and for example Skylake or possible Kabylake if that info is out there? Ofcourse the baseclock OCing making a comeback as mentioned by 1A. Any other things that are handy to know?

Not that I'm aware of.

[Gonio]

1 hour ago, M.Yurizaki said:

BCLK is useful for making finer adjustments. Every time you touch the multiplier, you increase the clock speed by BCLK amounts.

Ok, so I was correct for thinking that this allowed you for finer tuning, since you can also do in between steps. Say like for the OCers that want every mHz extra like : I run at 5166 instead of going only in steps of 100 each time where 5200 is not stable for example.

 

1 hour ago, M.Yurizaki said:

I think the concept of turbo boost once you have a good enough cooler goes out the window. Turbo boost is meant to pump up the cock speeds of fewer cores if the workload is high enough and the thermals allow for it. If you have a good enough cooler in that all of the cores can be in turbo boost all the time, then that idea is moot.

 

So you can basically think of overclocking as increasing the range at which your processor can run at. Adaptive power settings will still adjust the multiplier as needed.

Ok so if I am correct you confirm what I thought how it was: I see CPU boost as a method to give a bump in performance if the situation requires it. So if my OC is higher then the limit of the specified Turbo speed, you no longer have Turbo boost. But because adaptive mode lowers the speed when not needed you basically still have a turbo mode once it would be needed? Or am I thinking wrong now?

 

Thx for the info so far...