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asus z170-e with newest BIOS
intel core i5 6500, 3.2ghz
16gb gskill ddr4 2400
crucial mx200 500gb ssd
seasonic s12II-350w
win10 x64 home

so i want to run at max turbo speed of 3.6ghz all the time. asus has a UEFI setting called multicore enhancement which is suppose to accomplish this if you enable an XMP profile and set multicore enhancement to auto. i have done this and i get to 3.6ghz every few seconds but it is fluctuating from 33-36 multiplier which is causing the cpu to jump every few seconds between 3.3ghz, 3.4ghz, 3.5ghz and 3.6ghz in a random order. my temps are all within normal ranges so it doesn't appear to be a temp throttling issue.

i have windows power options set to high performance. i have tried almost every UEFI option regarding cpu throttling and it doesn't matter. i have tried setting cpu vcore to manual level of 1.2v instead of auto with no change. i have disable speedstep with no change. i have disabled c states but that will freeze the cpu at 3.3ghz without any fluctuations. i have it tried setting it per core and to sync all cores also with no change.

i have literally spent days trying everything in the UEFI and i am at a loss here. any idea what obscure UEFI setting it is that i am missing? i am running video off of the integrated intel cpu graphics, could this be the issue? i guess i can test with a spare videocard but this build is for a client and they did not want an separate gpu. really pulling my hair out here...

A few questions and thoughts...

Do you have the latest BIOS installed?

Does the behavior change at all if you disable Multicore Enhancement?

What are you using to put load on the system?

Yes, it is conceivable that it could be throttling to keep overall power draw in check, even though temps are nominal. Trying an external GPU might help you determine whether this is the case, even if it is your intent to use the IGP.

Multicore Enhancement is technically an overclock, since you're attempting to run the CPU out of spec (all cores at turbo frequency). Did your customer specifically request that you overclock the system to maximize performance? If not, then IMO you should just disable Multicore Enhancement and call it a day.

ryko wrote:

have done this and i get to 3.6ghz every few seconds but it is fluctuating from 33-36 multiplier which is causing the cpu to jump every few seconds between 3.3ghz, 3.4ghz, 3.5ghz and 3.6ghz in a random order.

I use to have locked Intel Xeon Ivy Bridge processor tried using a similar setting on a Z77 MSI motherboard, and observed the same behavior with clock speed fluctuating even when the processor was idle. Simply the Xeon was hard locked you were not allowed to adjust the multiplier.

What your witnessing is Intel's Turbo Boost kicking in for 2 cores with a light load (max turbo frequency), medium load it will drop down a multiplier, and for a heavy all cores loaded it drops down to processor base frequency.

On my 4790K at default settings it's processor base frequency set by Intel is 4.00 GHz but with a heavy load it actually runs at 4.2 GHz with all cores loaded the same should apply to your i5-6500. Try using CPU-Z to monitor the clock speed with a load over all cores it should be running slightly above the processor base frequency.

Time for the bad news, since you have a locked processor Intel removed the option starting with Haswell allowing you to force the Turbo Boost frequency over all cores so the Asus Multi Core Enhancement no longer functions on a locked processor unless you have a 6600K or the 6700K.

Found an old thread in the forums:
Overclocking non-K Intel CPUs? - The Techreport Forums

News post from the front page:
Intel removes modest 'free' overclocking from standard Haswell CPUs

biffzinker wrote:

Time for the bad news, since you have a locked processor Intel removed the option starting with Haswell allowing you to force the Turbo Boost frequency over all cores so the Asus Multi Core Enhancement no longer functions on a locked processor unless you have a 6600K or the 6700K.

Ahh, that would do it then. I thought the behavior sounded a lot like vanilla Turbo Boost, which is why I asked whether turning Multicore Enhancement off made any difference...

it was late last night, so i forgot to mention that this is idle behavior. i have stress tested with prime 95 x64 and then it will sit at 3.3ghz which seems really odd to me.

and yes i have seen that intel removed "free" overclocking on non-k cpus. but i thought that was just bclck which i am not messing around with at all. i have it set to 100 and it stays there.

secondly, i do have my personal gaming machine with a haswell core i5 4590 and an asus z97-a and i am able to peg that to a max turbo of 3.7ghz with no fluctuations. i have duplicated settings on the z170-e and it fluctuates. this is also why i thought it might be because of lack of an external gpu which my gaming machine obviously has. so i don't believe intel removed the ability to set to a max turbo starting with haswell but maybe starting with skylake? could this be a skylake specific behavior?

i have to get back to work but i will test later today by disabling multicore enhancement and with an external gpu. thanks for any more thoughts.

ryko wrote:

and yes i have seen that intel removed "free" overclocking on non-k cpus. but i thought that was just bclck which i am not messing around with at all. i have it set to 100 and it stays there.

The BCLK thing was recent. Disabling Multicore Enhancement on non-K CPUs apparently happened a couple of years ago.

I think I might of been wrong, if I remember correctly what Intel removed was the ability to increase the multiplier 4 steps up from the highest Turbo multiplier. So using your i5 6500 as an example, when it Turbos to 3.6 GHz on a couple of cores at one point in the past you would of been allowed to add another 4 to 36 multiplier giving you 4 GHz clock speed on two of the cores. That what Intel removed starting with Haswell.

Lets try something else to find out for sure. Boot into the uEFI, select the manual setting, sync all cores, and set the multiplier to 36. Let me know if this works.

that is the strange thing...there is nowhere to manually set the multiplier. unless it is hidden behind some un-descriptive term in the UEFI that i can't find. doing some more testing now and will report back.

some testing updates...

disabling multicore enhancement makes the cpu operate normally at 3.2ghz idle and 3.3ghz under 4 core load. only able to get up to 3.5ghz under 1 core load though...not 3.6ghz like it should. i also re-tested on a per core basis with multicore enhancement enabled and i only get to 3.5ghz on 1 core...it actually repeats the fluctuating behavior either way unless i disable c states which makes it sit at 3.3ghz!

testing with an external gpu results in the same fluctuating multiplier behavior as before...unless, of course, c states are disabled and it is at 3.3ghz.

i have gone back and flashed multiple older BIOSes instead of the newest one which i was running and the results are the same. tried original BIOS version of 0230 and version 1203 as well as the newest version 1602 and still the same fluctuations.

i am just going to give up and disable the c states which will give me a steady 3.3ghz at idle and load...so frustrating! guess it is a skylake specific behavior? anybody else have a non-k skylake that they can test to confirm with multicore enhancement?

I found a thread earlier when searching duckduckgo the person reported success with a locked Xeon CPU following the steps in my above reply. Figured it was worth a shot.

Edit: I rebooted and wrote down were you should find the settings for "syncing all cores" to same multiplier. This is on a Z97 Asus motherboard so if might be different although I doubt Asus has changed the Gui layout.

Go to Ai Tweaker, down to Ai Overclocker Tuner switch it to manual, then go down to CPU Core Ratio switch the setting to Sync All Cores, and then move down to 1-Core Ratio Limit type in 36. Go to save settings reboot.

You have to enable SpeedStep with Turbo Boost for it turbo to 3.6 C-states doesn't have any effect other than for power management.

yes i had speedstep enabled along with turboboost and multicore enhancement yet i still don't get to the max turbo of 3.6ghz...c-state is the only thing that would keep the multiplier from fluctuating. i have all other asus power saving features disabled also but no difference.

i delivered the pc to the client this evening so i don't have it for further testing. i might just stop by there tomorrow though and see if i can't manually set the multiplier to 36 like suggested by biffzinker. i did have it set to sync all cores, but i will try the 1-core ratio limit which seems promising. why they couldn't just label it multiplier instead i will never know.

Given that you already delivered the PC, I'd be inclined to just let it go since you won't be able to perform extensive stability testing.

Update:

finally got over to the clients house for some more testing. i tried manually setting the multiplier exactly as suggested by biffzinker but it doesn't work. in the UEFI, it looks like 36 is accepted on all cores as the multiplier, but once in windows i get the same fluctuations still! arghhh!!! i spent an hour redoing and redoing settings that i had already changed a hundred times but no luck. i am chalking it up to a skylake thing unless someone has some other proof. maybe it's an asus z170 thing? curious if another mobo manufacture has the same behavior with skylake non-k cpus...

also another issue has appeared according to the customer. win10 doesn't want to resume from sleep with any sort of regularity. i tried re-enabling c-states to see if it would make a difference as well as disabling multicore enhancement but it did not. seems totally random when it wants to come out of sleep or not. i did notice the hdd activity light seems to blink occasionally while sleeping though. so it appears like it is not fulling going to sleep and therefore can't resume. screen goes blank though. i messed around with advanced power options and sleep behaviors but no change so far. a bit of googling confirms that many other people are having the same issue with win10 so hoping maybe microsoft will push an update to address it.

Why? This is like the computing version of a truck rolling coal.

Sleep problems are often caused by buggy device drivers, so MS may not be able to do anything until whatever vendor screwed up their driver fixes it. You could check whether there are newer drivers available for the various devices in the system...