9900k voltage dramatically up from 4.8 to 4.9 GHz?

[Melodist]

Hello there,

 

I've been overclocking my 9900k and realized it's running with 1.225 volts at 4.8 GHz but only starts to be stable with 4.9 starting at 1.29 volts, is that normal or may I have to tweak something because the gap here from one to another speed is huge in terms of what voltage I have to add.

 

[5x5]

It's normal. That's the reason the 9900K is a space heater. It needs the voltage to sustain the frequency.

[xenonhelix]

That is pretty normal, around 5ghz all Intel chips require increasingly more voltage. It's up to you if the decreased lifetime and added heat is worth it.

[Constantin]

Just install a decent cooler, you will be just fine

I run my 9700k with a crap 40$ air cooler and i am just fine (summer here ambient ~30c)

[Zberg]

Normal (my 4.9 all core is at 1.3), and also unfortunately highly variable between chips (very broad silicon lottery on 9900k).  I have heard all core 5.0's from as low as 1.27 all the way up to 1.37 from talking with different people.

[Zberg]

Also the gaps arent always linear, mine is OK from 4.8-5.0 but to get 5.1 voltage requirement jumps very substantially (with enough heat to keep my office warm in the winter time lol)

[Melodist]

Yeah but going from 4.8 at 1.225 to 4.9 at 1.29 is huge? Like, it's not worth putting that much voltage on it for mere a 100 MHz merit and having to deal with high temps.

 

With 4.8 at 1.225, it runs 80 degrees package temp Prime 95 AVX full load on a Noctua NH-U12A.

[xenonhelix]

1 minute ago, Melodist said:

Yeah but going from 4.8 at 1.225 to 4.9 at 1.29 is huge?

It's not horrible but it's not great either

[Melodist]

1 hour ago, Zberg said:

Normal (my 4.9 all core is at 1.3), and also unfortunately highly variable between chips (very broad silicon lottery on 9900k).  I have heard all core 5.0's from as low as 1.27 all the way up to 1.37 from talking with different people.

I saw a delidded 9900k with custom IHS going under 1.2v so yeah

 

But I'm wondering whether i'm stressing my CPU too much with Prime 95 FFT 12 because der b8uer is running 1344 and I only benched my 6900k back in the day with 1344 either. Maybe I should test it with 1344?

[5x5]

47 minutes ago, Melodist said:

I saw a delidded 9900k with custom IHS going under 1.2v so yeah

 

But I'm wondering whether i'm stressing my CPU too much with Prime 95 FFT 12 because der b8uer is running 1344 and I only benched my 6900k back in the day with 1344 either. Maybe I should test it with 1344?

For Intel, anything under 1.35 is safe with 1.4 being on the edge.

[Vejnemojnen]

Achievable clock speeds and required voltage are not linear.  You should aim for a sound balance of speed, temperatures and voltage imho. Sometimes that last few hundred MHz just simply don't worth the effort and extra volts. 

[NDRE28]

My Intel i7-9700K runs at 4.7GHz with default BIOS settings, no overclock. 

[Melodist]

But then again, is maybe my stress testing too tough? I'm doing 12k small ffts in Prime 95 and I saw der b8uer testing his CPUs on 1344?

 

 

[Melodist]

It does make a difference when I put it to 1344 obviously, which is still lots of load.