Help! my CPU multiplier is limited all of sudden to x35!!!!

[TickleMeRifle]

so i went on holiday for 3 weeks and came back home. as expected there were all these windows 10 updates waiting for me which i was obviouslly forced to wait before i could resume my business on the PC. After they finished and installed though I noticed my CPU speed maxed out at 3.5Ghz....this was strange as it's always been overclocked to 4.2Ghz. I rebooted my PC and went into the bios....no settings had changed AT ALL. the multiplier was still at 42 for each of my cores (I have an i7 6950x which has beeing running a CONSTANT 4.2Ghz for 3 years. Speedstep has been turned OFF). I also have a 5.25 bay which has an LCD readout of my current CPU speed and whilst in the bios and booting up it READS 4.2 Ghz. HOWEVER 15 seconds into logging into windows 10 the 4.2 drops to 3.5. CPUz reads the multiplier dropping back to x35 for some strange reason after logging in! This confirms it's a software issue however I have not installed anything other than the windows 10 updates??? could it be the updates screwed me over???

EDIT: yup confirmed guys. . did a bit of digging a windows update is the culprit! (specificaly KB4100347) other users have reported same thing with updates since last month! but it only occurs on broadwell-E cpus!

[Bad 💀 Motha]

Control your Windows Updates and that wouldn't happen. Users have full control over all that, u must configure it though. Settings > Windows Updates and also in there is Advanced and other options. There is also a Pause feature too.

For business then u should use Win10 Pro, which users can defer Windows Updates for up to 90days IIRC

Probably what has occurred is the PC was off so long, the CMOS battery is not holding up, resulting in the CMOS to reset back to default settings, so your OC'ing is no longer set to "manual"

Test the cmos battery voltage, replace it if below 2.9-3.0 Volts

[chiefputsilao✖️ping]

bios settings remains unchanged so it may not be a dead/dying CMOS battery.

if upon using the pc the cpu frequency drops from 4.2ghz to 3.5ghz, then it may be a result of thermal throttling.

[TickleMeRifle]

İlk olarak Bad 💀 Motha tarafından gönderildi:

Control your Windows Updates and that wouldn't happen. Users have full control over all that, u must configure it though. Settings > Windows Updates and also in there is Advanced and other options. There is also a Pause feature too.

For business then u should use Win10 Pro, which users can defer Windows Updates for up to 90days IIRC

Probably what has occurred is the PC was off so long, the CMOS battery is not holding up, resulting in the CMOS to reset back to default settings, so your OC'ing is no longer set to "manual"

Test the cmos battery voltage, replace it if below 2.9-3.0 Volts

the problem was though that this was a cumulative update . this one: https://support.microsoft.com/en-us/help/4462919/windows-10-update-kb4462919 which was only released yesterday

İlk olarak chiefputsi✖✖✖ 上 没什么 老挝 tarafından gönderildi:

bios settings remains unchanged so it may not be a dead/dying CMOS battery.

if upon using the pc the cpu frequency drops from 4.2ghz to 3.5ghz, then it may be a result of thermal throttling.

i even used 3 prior bios versions which were KNOWN to have worked for me in the past and still i get the downclocking...totally weird! the multiplier just goes from 42 to 35. If i sit at the password login screen it's still running at 4.2 as soon as i put my password in and press ENTER bam it goes to 3.5Ghz

[Clint E]

Probably stating the obvious but I had same issue with my 5820k , turned out to be a power saving issue (don’t remember what I did), might be a place to start

[TehSpoopyKitteh]

İlk olarak Quokka tarafından gönderildi:

İlk olarak chiefputsi✖✖✖ 上 没什么 老挝 tarafından gönderildi:

bios settings remains unchanged so it may not be a dead/dying CMOS battery.

if upon using the pc the cpu frequency drops from 4.2ghz to 3.5ghz, then it may be a result of thermal throttling.

i even used 3 prior bios versions which were KNOWN to have worked for me in the past and still i get the downclocking...totally weird! the multiplier just goes from 42 to 35. If i sit at the password login screen it's still running at 4.2 as soon as i put my password in and press ENTER bam it goes to 3.5Ghz

It’s likely throttling to conserve power. If you’re playing a game and it goes up, it usually means you’re no longer under an idle state and under enough load to warrant full use of the CPU.

[DefeatedBroom74]

Probs windows power managment turn to high performance should always run at 4.2
Dont mind windows 10s maximum speed for your cpu just watch the speed
ex mine says Maximum 3.6 but under speed everynow and then it jumps to 4.6-4.8

[TickleMeRifle]

nope just tried virtually every demanding game in my steam library even tried running a dozen demanding applications all at once that I KNOW in the past hit 4.2 BUT NOTHING goes past 3.5 anymore despite the SAME bios settings! high performance is already selected as a power profile with 100% cpu usage as min and max selected. nothing has changed in bios or windows except one stupid update from windows since i came back from holidays! far out what a ball breaker windows updates are!

yup confirmed guys. . did a bit of digging a windows update is the culprit! other users have reported same thing with updates since last month! but it only occurs on broadwell-E cpus!

[🦊Λℚ𝓤ΛƑΛᗯҜᔕ🦊]

Did you actually check cpu-z to see if it's actually running at 3.5 ghz or 4.2 ghz? Don't rely on the windows task manager. It's often wrong.

[TickleMeRifle]

İlk olarak Impending Rentacle Tape tarafından gönderildi:

Did you actually check cpu-z to see if it's actually running at 3.5 ghz or 4.2 ghz? Don't rely on the windows task manager. It's often wrong.

yup it was running at 3.5ghz on cpuz and on my 5.25 LCD display. I finally managed to get it back to 4.2.....but the path there was strangelky time consuming. I narrowed it down to the windows update KB4100347 however unlike other people who just uninstalled it and got their overclocks working uninstalling mine did not work! It wasn't until i installed and uninstalled it a whopping 10 times did my overclocks work again. ♥♥♥♥♥♥ windows updates can be a pain in the ass! I then used another third party program to block that update for good!

[chiefputsilao✖️ping]

^report at microsoft forum so a proper fix can be relased in the future.

KB4100347 is needed for protection against spectre...
https://support.microsoft.com/en-ph/help/4100347/intel-microcode-updates-for-windows-10-version-1803-and-windows-server

[Clint E]

İlk olarak Quokka tarafından gönderildi:

yup confirmed guys. . did a bit of digging a windows update is the culprit! other users have reported same thing with updates since last month! but it only occurs on broadwell-E cpus!

Wow I have my updates on pause thanks for the headsup on this, will keep waiting

[Bob the Boomer]

windows 10 feature, love seeing how well this OS is going

[TehSpoopyKitteh]

İlk olarak C= 64 tarafından gönderildi:

windows 10 feature, love seeing how well this OS is going

That isn't a Windows 10 feature. It is the lack of one. MS updated for Spectre and Meltdown twice so all the OP has to do is check for updates again.

[pasa]

İlk olarak C= 64 tarafından gönderildi:

windows 10 feature, love seeing how well this OS is going

It refers an intel microcode update -- likely other OSes also get it. Friendly ones may make it configurable.

[TehSpoopyKitteh]

İlk olarak pasa tarafından gönderildi:

İlk olarak C= 64 tarafından gönderildi:

windows 10 feature, love seeing how well this OS is going

It refers an intel microcode update -- likely other OSes also get it. Friendly ones may make it configurable.

I do appologizs for initially sounding ruse and standoffish. The thing is that KB articles aren't always going to be about Feature Updates (ie Windows 10 1809). The microcode updates were actually security hotfixes.

What the microdcode update did was remove a vulnerability that left data being processed by the CPU to be intercepted on the fly and stored temporarily, and then skipped if not needed This was a great hold and wait performance feature that had been around since the Pentium MMX days but geneally speaking two groups found a way to explloit it and named them Spectre and Meltdown.

Mind you I am running on Windows 10 with a Core i7-6700K and literally felt no difference in poerforamce. Not sure about meltdown, but the first update should be from the OP's motherboard manufacturer and the MS Microcode update,a nd the second should be from the motherboard manfacturer. MS then released another hotfix to adress the issues the OP was having.

Anyway, TLDNR. The point being that I understand what you are saying. Just in order for that first microcode update to work properly, they have to upgrade the BIOS to the lateast version...which should be a breeze for the x99 board they are using.