Doubts on i5 8600k OC

[xubeiga]

Hello guys!

I just entered in the Overclocking world and i did an OC to my 8600k to 5GHZ at 1.30V.
Everything seems fine till now, i did a prime95 stress test for about 30 minutes and nothing failed (i know its not much time but its ok)

I just have some doubts about the OC yet, specifically about the options on BIOS.

1) I dont want my 8600k to be on 5GHZ all the time, i mean, when i'm just browsing there's no need to be on 5GHZ right? I want him to be on 5GHZ just when he needs too, which is when i'm gaming (I don't use the PC for rendering or other stuff, i just game on it).

What options should i let enabled on BIOS for that to happen? I disabled all C states and also Intel Speed Shift Tech but i let the EIST enabled. Is that right?

Also, is it possible to make the vcore low when he's on idle without affecting the stability of the system? I believe that my CPU is always at 1.3V as i setted on BIOS and because i disabled those C States options, but i did cause i read that it might compromise the stability if i let it enabled.

2) When i open the HW MOnitor to see my CPU Temps, its very good on idle and gaming. On idle, it stays at 35 C at max and gaming it goes to 65 C at max, but staying on 60 C most of the time.
The question is: I have some "spikes" on my cpu temp, which is very weird. At this very moment im checking the HW Monitor and the temperatures on the CPU are like i said, on 35C at max. But suddenly the temp jut go to like 60 C for less than a second and then go back to the 35C. Is this normal? Or is something i didnt setup right on BIOS?

 

[Nebulous]

Congrats on the 5.0Ghz oc! Leave all the power saving features on. This will allow the chip to downclock, save power and lower temps. When it's time to game ( or any other intensive workload) the chip will resume the 5.0Ghz overclock and hold it there until you get out of the game. Then it will revert to it's lowest clock speed.

Me, I leave my 5.0Ghz overclock 24/7 since day one

 

[Mr.Scott]

While the above is true, sometimes the P-states shift will cause enough instability to BSOD your machine. You may have to make some adjustments.

 

[xubeiga]

Hello guys!
First of all, thanks for the anwers

While the above is true, sometimes the P-states shift will cause enough instability to BSOD your machine. You may have to make some adjustments.

By sometimes you mean even when i'm on idle? I'd like to save energy like i said, but i prefer stability...I'd hate my pc BSODing from time to time
What adjustments you think i'll have to make?

 

[Nebulous]

For the amount of energy you're saving, it's not recommended to use less voltage that will cause instability. The adjustments needed will be so miniscule, you won't even lose anything. The PC will still downclock.

 

[xubeiga]

Guys, i downclocked to 4.9GHZ and 1.29V cause i wanted to low the temp when gaming. CPU was hitting almost 70C and i want it to be 65C or less. I know 70C is still OK but i want it to be at 65C max.

I did some test on P95 after downclocking for stability and i saw something strange on VCore. The VCore according to HW Monitor went down to 1.168V and stood there all the 30 minutes of stress testing, is this right?
When i stop the test, the VCore back to 1.284. Isnt it weird? when stress testing the cpu vcore goes down to 1.168V? ^.-

Another doubt is: I setted 4.9GHZ and 1.290V on BIOS.
As the image shows, in HW Monitor the colunm MAX CPU VCORE shows 1.296V.
Why is the CPU going to 1.296 if i limited it to 1.290 on BIOS?

 

[Mr.Scott]

The drop you see is called vdroop. It can be corrected with LLC.
It is normal for the bios to over or under volt slightly on settings, so that's a non-issue.

 

[xubeiga]

Ah, thanks. Good to know!

Another question:
I was playing Shadow of the Tomb Raider and the CPU was in 98% Usage and the clock was on 4600Mhz. Why didnt he go to 4900Mhz, like i setted on bios?
I kept monitoring the clock while playing and the cpu rarely went to 4900mhz and i thought ok, maybe he is not going there cause he doesnt need to. But in the image below, on a part of the map he was almost at 100% usage and still at 4600mhz... Is there a reason for that? When i did a stress test on P95, all cores worked on 100% and 4900mhz though...is it maybe a game issue?

 

[xubeiga]

Lol, i changed the LLC on Bios to TURBO and stress tested with P95 and in 30 seconds the cpu temp went to 84 C. I just stopped the test immediately.

I dont understand. What would this LLC fix exactly? So when i did the test before and in HW Monitor it showed 1.168V, it was showing wrong? Why changing to turbo the temps went so much higher?

I tried editing my last post, but i cant find the edit button.

 

[xubeiga]

Ah, thanks. Good to know!

Another question:
I was playing Shadow of the Tomb Raider and the CPU was in 98% Usage and the clock was on 4600Mhz. Why didnt he go to 4900Mhz, like i setted on bios?
I kept monitoring the clock while playing and the cpu rarely went to 4900mhz and i thought ok, maybe he is not going there cause he doesnt need to. But in the image below, on a part of the map he was almost at 100% usage and still at 4600mhz... Is there a reason for that? When i did a stress test on P95, all cores worked on 100% and 4900mhz though...is it maybe a game issue?

Ok i finally understood what was happening here. I setted AVX Offset to -3 on BIOS so it is on 4600MHZ when playing. I didn't know that the game would use this AVX thing. Is it safe to change back to 0 so i can have 4900MHZ all the time when playing the game or is it better to just let it on 3?

 

[Mr.Scott]

LLC will increase the voltage to closer to what you set, to alleviate vdroop. Yes, it will increase temps, anytime you increase voltage temp will go up.
AVX is tough on CPU's. It will test your stability and temps like nothing else will. A negative offset will keep your temp in check by lowering your clocks and voltage as more AVX instructions are used. If you set that back to 0 you will get your clock speed back but your temps will skyrocket and you will probably throttle. It is a balancing act.
Bottom line is, your overclock isn't as great as you think it is.
I would look at a guide or two to help you along. Most of your questions are basic overclocking and stress testing questions. You are expecting too much from your system.

 

[xubeiga]

LLC will increase the voltage to closer to what you set, to alleviate vdroop. Yes, it will increase temps, anytime you increase voltage temp will go up.
AVX is tough on CPU's. It will test your stability and temps like nothing else will. A negative offset will keep your temp in check by lowering your clocks and voltage as more AVX instructions are used. If you set that back to 0 you will get your clock speed back but your temps will skyrocket and you will probably throttle. It is a balancing act.
Bottom line is, your overclock isn't as great as you think it is.
I would look at a guide or two to help you along. Most of your questions are basic overclocking and stress testing questions. You are expecting too much from your system.

Ok so i gotta ask, do i really need to mess with LLC on my case?
Even with this vdrop i survived to a 40 minute prime 95 test and Shadow of the tomb raider all night long with 4.9Ghz all the time with good temps.

I have a good system though, i have a z370 Mobo and a H5 Universal cooler and a very good case. From what ive read it is easy to get to 4.9 or 5ghz with 8600k and 1.29V shouldnt have made my cpu temp go to 84c immediately, so I guess what did it was the Turbo LLC...

And this Vdrop doesn't make any sense to me, if the Vcore drops to 1.168 with 4.9Ghz on full load, shoudnt the system just fail right away? 1.168V is like impossible to keep 4.9Ghz...

 

[Mr.Scott]

Easy to hit 4.9-5.0 is subjective to the quality of the CPU. They're all not created equal. Stability is another thing. Just because you can hit those speeds doesn't mean it's stable. 40 minutes of prime is not enough. 2 hours minimum.

On the LLC, no, you don't need to use it. You can just bump up the vcore to cover the droop. In either case, your temps will go up.
Your cooler is rated for 160w max. Your CPU w/overclock is probably coming close to that.

 

[trents]

You are too obsessed with keeping a low temp. Anything up to 90c, even for long periods, is fine and safe. If you want to run at higher overclocks and get cooler temps you need to either delid or invest in better cooling or both.

 

[Mr.Scott]

You are too obsessed with keeping a low temp. Anything up to 90c, even for long periods, is fine and safe. If you want to run at higher overclocks and get cooler temps you need to either delid or invest in better cooling or both.

Right on.

 

[xubeiga]

Well, i've decided to leave LLC on Auto even with the vdrops. 1 hour of P95 and games running without any problems at 4.9GHZ i don't see why i should care about this vdrop actually.
I'll just stay with 4.9GHZ 1.29V and LLC on Auto, if anything happens then i'll think through again.

Anyway, thanks everyone who helped with my doubts!