# i5-8400, I read some mobo's can make it do full 4ghz and some 4,2ghz?



## Space Lynx (Nov 3, 2017)

Just curious if anyone knows what motherboards can achieve this, currently doing a second rig for a friend at the moment, we can get the i5-8400 to sit steady at 3.8ghz all 6 cores 24.7 with MSI OC Genie in BIOS... no downclocking ever... but we can't hit the magic 4ghz or 4.2ghz mark, Intel says 4ghz... feels kind of misleading.


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## Hawkster222 (Nov 3, 2017)

Hi there Lynx 

I myself never had the opportunity to work on a Z370 motherboard and should someone else have a more valid answer or suggestion please feel free to indicate so. 

SHORT ANSWER : Asus boards , not sure which one tough I beleive all of them 

LONG ANSWER :

To my knowledge what you are talking here about is called MEC (multi core enhancement ) I do know MSI and ASUS boards have this feature not sure if Gigabyte ,Asrock and ECS boards do as well they should I suppose , basically to my knowledge it allows the CPU to run at its Asus boost\ intel boost clock speed the cpu can go in optimal temps basically like the CPU turbo clock 

so if you have a 8400 I5 by default the chip will run one core at 4 ish ghz the other will be in the back with lower clocks 

so what MEC does is it turbo clocks all the cores to 4 ish ghz 

I am not sure if you can post links here but Jay two centz he made a vid where his and Dimitri benchmark on the I7 K where they ran it at stock levels the benchmarks where night and day compared to Bitwit and another reviewer . 

also I know some boards dont even  have MEC enabled by default.

Hope it helps.


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## R0H1T (Nov 3, 2017)

MCE doesn't work on non K processors anymore, unless someone has real life evidence to prove otherwise. So no you won't get *all core* 4GHz, or higher, *turbo* locked even with a Z370.


lynx29 said:


> Just curious if anyone knows what motherboards can achieve this, currently doing a second rig for a friend at the moment, we can get the i5-8400 to sit steady at 3.8ghz all 6 cores 24.7 with MSI OC Genie in BIOS... no downclocking ever... but we can't hit the magic 4ghz or 4.2ghz mark, Intel says 4ghz... *feels kind of misleading*.


Yes it is that's why we've had this, just in the recent past ~ On Intel's Decision to no Longer Disclose All-core Turbo


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## Space Lynx (Nov 3, 2017)

Hawkster222 said:


> Hi there Lynx
> 
> I myself never had the opportunity to work on a Z370 motherboard and should someone else have a more valid answer or suggestion please feel free to indicate so.
> 
> ...




We are using the MSI Z370 A-Pro motherboard. Trying to find the setting you speak of... will be back in an hour or so, going to tinker with BIOS for awhile, maybe turn off OC Genie and see if it will let me tinker around.


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## Flaky (Nov 3, 2017)

Max what you'll get is 3.8GHz with all cores loaded.
The last architecture where it was possible to turbo-lock one core frequency for all was haswell.


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## Space Lynx (Nov 3, 2017)

Flaky said:


> Max what you'll get is 3.8GHz with all cores loaded.
> The last architecture where it was possible to turbo-lock one core frequency for all was haswell.



Read what Hawkster said, it seems if you own MSI or ASUS mobo you can still hit 4ghz instead of the 3.8 on all 6 cores no downclocking... hmmm... I wonder if I should try Throttlestop, probably won't work, but I can't find the option in my MSI bios, dangit! I need to refund this one and find the right Asus one... reports are that Asus model can do 4.2ghz on the i5-8400


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## R0H1T (Nov 3, 2017)

lynx29 said:


> Read what Hawkster said, it seems if you own MSI or ASUS mobo you can still hit 4ghz instead of the 3.8 on all 6 cores no downclocking... hmmm... I wonder if I should try Throttlestop, probably won't work, but I can't find the option in my MSI bios, dangit! I need to refund this one and find the right Asus one... reports are that Asus model can do 4.2ghz on the i5-8400


No you can't, try it yourself if you must, but you can't go past *Intel's locks* using some random MB or software hack ~


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## CAPSLOCKSTUCK (Nov 3, 2017)

I quickly looked at HWBot

fastest   i5 8400 running R15 is 4.1ghz using  MSI Z370-A Pro






http://hwbot.org/submission/3689139_apex_oc_cinebench___r15_core_i5_8400_1012_cb


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## Space Lynx (Nov 3, 2017)

CAPSLOCKSTUCK said:


> I quickly looked at HWBot
> 
> fastest   i5 8400 running R15 is 4.1ghz using  MSI Z370-A Pro
> 
> ...




I WISH I KNEW HOW TO CONTACT THIS PERSON, THATS THE SAME MOBO AS ME!!! HOLY CRAP lol... sorry for all caps... agh... im going to go tinker in BIOS more


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## R0H1T (Nov 3, 2017)

CAPSLOCKSTUCK said:


> I quickly looked at HWBot
> 
> fastest   i5 8400 running R15 is 4.1ghz using  MSI Z370-A Pro
> 
> ...


That 4.1 (single core) is due to BCLK OC, once again the *turbo will not exceed 3.8GHz* (probably 3.9 due to BCLK OC) on all cores.

This is just to clear any misapprehensions the OP, or anyone else might have wrt the locked i5 or i3 being paired with a Z370.


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## Space Lynx (Nov 3, 2017)

R0H1T said:


> That 4.1 (single core) is due to BCLK OC, once again the *turbo will not exceed 3.8GHz* (probably 3.9 due to BCLK OC) on all cores.
> 
> This is just to clear any misapprehensions the OP, or anyone else might have wrt the locked i5 or i3 being paired with a Z370.




Still gains 50 points in Cinebench... so I am not sure what you mean, because that is a multi-core score posted of C15.  Please explain?


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## Hawkster222 (Nov 3, 2017)

Like I also said in my fist post I never played around on a Z370 mobo , so I dont know the tricks and magic to get that 4 ghz number and agian I speak from my understanding and feel free to correct me. 

But I feel the best way to get a solid answer is find a reviewer that tested this in depth on multiple mobo's because something is up with these MSI and ASUS boards.


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## acidsys (Nov 3, 2017)

Hawkster222 said:


> Like I also said in my fist post I never played around on a Z370 mobo , so I dont know the tricks and magic to get that 4 ghz number and agian I speak from my understanding and feel free to correct me.
> 
> But I feel the best way to get a solid answer is find a reviewer that tested this in depth on multiple mobo's because something is up with these MSI and ASUS boards.



@lynx29 @Hawkster222

Both msi and asus boards will never run MCE with the I5-8400.

R0H1T is 100% right on is one as the 4.1ghz cine15 sub was only running at 3.91.

This is a cinebench r15 run with MCE set at 40x. But with C-states disabled to stop any single core turbo boost. Run on a Asus z370 Apex.


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## cadaveca (Nov 3, 2017)

Best you will get with most motherboards is 3.9 GHz on all cores, boosting to 4.1 on one core. You do this with BCLK OC, up to 102.5 MHz. Many boards will start to fail @ 102.55 MHz

It will look like this in BIOS:


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## Space Lynx (Nov 3, 2017)

cadaveca said:


> Best you will get with most motherboards is 3.9 GHz on all cores, boosting to 4.1 on one core. You do this with BCLK OC, up to 102.5 MHz. Many boards will start to fail @ 102.55 MHz
> 
> It will look like this in BIOS:




thank you I found it, you are right. I am rocking 3.9ghz all 6 cores no downclocking, and sometimes i do get boosts to 4.1 ghz on one core now, hey I can't complain, it was cheap lol


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## SARWIN (Oct 22, 2019)

cadaveca said:


> Best you will get with most motherboards is 3.9 GHz on all cores, boosting to 4.1 on one core. You do this with BCLK OC, up to 102.5 MHz. Many boards will start to fail @ 102.55 MHz
> 
> It will look like this in BIOS:


Hi Sir,

I'm using i5 9400F 2.9GHz BCLK with MSI Z390 MPG Gaming Plus mobo engaged with 32Gb ram 3200MHz.
Planning to run at 4.0 GHz with 32GB ram at 3000MHz. can you please show me the full set up, that I have to do in the BIOS OC setting.

Really dumb to say...
I have set up earlier
CPU Ratio: 41
Ring Ratio:39
CPU Base Clock:102.27MHz
DRAM Frequency:3000MHz

Result:
CPU temp:45%
Mobo temp:43%
CPU Speed:4.08GHz
DDR Speed:3000MHz

Stress Test: 1 hour:
CPU temp:67%
Mobo temp:56%
CPU Speed:4.1GHz

Task Manager:
CPU:35%
MEMORY:48%
(only open Google Chrome)

No lagging. But if open 3 hard software(Autodesk Revit, Autocad, C3D) that uses 4 cores. the CPU usage reaches 90%!. Please guide me what should I do in this matter.


Please attached here with a full snapshot of the BIOS OC screen with the settings.


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