killthespam

Help with CPU speed fluctuation with HT on please

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Just noticed on task manger WIN10 64 Z370 GaminPlus MB with I8700K OC @ 4.9 while HT on, CPU speed is bouncing up and down between 4.88 and 4.60.

Same settings but HT off (no other change) speed is constant at 4.88 and P3Dv4.2 is smooth. I don't understand what is creating this issue having in view that the only change is HT from ON to OFF. This CPU variation on speed is

creating stutters in P3Dv4.2. 

Any help is greatly appreciated.

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Posted (edited)
13 hours ago, killthespam said:

Just noticed on task manger WIN10 64 Z370 GaminPlus MB with I8700K OC @ 4.9 while HT on, CPU speed is bouncing up and down between 4.88 and 4.60.

Same settings but HT off (no other change) speed is constant at 4.88 and P3Dv4.2 is smooth. I don't understand what is creating this issue having in view that the only change is HT from ON to OFF. This CPU variation on speed is

creating stutters in P3Dv4.2. 

Any help is greatly appreciated.

See if these forum posts helps you at all:  

 

Seems some are seeing better results with HT off.  Not sure if that's the majority as I currently run my 6700K with HT on and not really seeing the speed variation.  

 

Edited by DylanC

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What you are experiencing can be indicative of running HyperThreading.  If you're desire is to run with HT on, then you'll likely have to play a bit with Affinity Mask settings to mitigate the effect you're experiencing.

Best wishes.

 

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15 hours ago, killthespam said:

Just noticed on task manger WIN10 64 Z370 GaminPlus MB with I8700K OC @ 4.9 while HT on, CPU speed is bouncing up and down between 4.88 and 4.60.

Same settings but HT off (no other change) speed is constant at 4.88 and P3Dv4.2 is smooth.

This has little to do with HT and everything to do with CPU Core Parking.  For simming you'll want to insure Core Parking is disabled.  More info here: http://www.overclock.net/forum/297-general-processor-discussions/1544554-core-parking-windows-disable-more-performance.html

and here:

The best utility (read: safest) for managing Core Parking is from Bitsum (the guy who makes Process Lasso): https://bitsum.com/parkcontrol/

I simply disable Core Parking in the Registry... there are better ways to save energy while computing.

HTH,

Greg

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Thank you folks!

What I don't understand is that I didn't have this issue before with HT on and now suddenly it looks like a problem. Very strange. 

Greg, thanks, I did disable Core Parking as you mentioned in registry, also used Lasso. Unfortunately I have the same results.

DaveCT2003 and DylanC, also thank you, it looks like there are two categories of people using HT differently with significant results. 

Again, your help and guidance is greatly appreciated.

 

 

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7 hours ago, killthespam said:

What I don't understand is that I didn't have this issue before with HT on and now suddenly it looks like a problem. Very strange.

Could you clarify "before"?  When did this situation start?

Thanks,

Greg

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Certainly, I noticed this issue about 6 days ago while watching the  Task Manager. I had no updates, no changes whatsoever.

I was trying to figure out  why I have stutters on P3dV4.2, initially I checked  under windows-display settings to see if my monitor is still at 30 HZ (a few times it did change to a different number) and that was not the case. So I opened the Task Manager and noticed that issue with HT ON. I don't know why I just changed HT from on to off and no stutters at all.

I cannot find any explanation to this, I tried what  Greg, DaveCT2003 and DylanC mentioned and unfortunately no success.

On my MB I have:

CPU ratio mode is FIXED MODE

CPU ratio offset when running AVX = 0

Digi power - CPU loadline calibration control - MODE4

Intel C State = Disabled

CPU cores un-parked

 

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Posted (edited)

Ht on , have you avx 3 ( see that you hve 0 ) set in bios or you trip the cpu powertarget with downclock as suposed, problem with VRM temp?

I have no problem to run my 8700k at 5.3ghz HT on , I run avx0 and extended Cpu power settings.

Cpu loadline have nothing to do with CPU powersettings , only to calibrate vcore during load

I Run ASUS not familar with GA bios on MoBos after Z97

Edited by westman

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Ok, I'll try avx at 3. Do you think that value will stop the cpu speed to fluctuate?

 

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Posted (edited)
2 hours ago, killthespam said:

Ok, I'll try avx at 3. Do you think that value will stop the cpu speed to fluctuate?

 

No it shall fluctulate 300mhz with 3 and no fluctulating with 0, that wy suspect that you exided the deafault power limit the CPU clock itself down , you have small avx bursts in p3d that reqest more power then when it no avx the powerdraw decrease and cpu clock back to 4.9.

the powerdraw is much lower with HT off and not trip the Cpu powerlimit.

you have both thermal ( overheat) and power limits

my eng is bad , hope you get it

Edited by westman

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Yes I understand what you say, thank you. Interesting, in XP11 I don't see this issue, all the cores are almost even and no spikes at all.

Again, many thanks.

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3 hours ago, killthespam said:

Yes I understand what you say, thank you. Interesting, in XP11 I don't see this issue, all the cores are almost even and no spikes at all.

Again, many thanks.

Does XPlane use AVX extensions? If not, that would would explain it.

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Interesting question, just found this, I don't know if is true or not from plane org:

The last time anyone from LR answered a question about AVX use (early last year), the answer was that they don't use AVX, but SSE2 instead because there was no advantage in using AVX in XP at that time. I don't see any evidence that's changed, and it certainly isn't where development efforts are right now, or where they've been since that time.

I have not seen any evidence that AVX is used by XP alone. However, Windows itself uses it in the background, not a lot, but it's noticeable. If you have an AVX offset in your OC profile, monitor the CPU clocks real time and you will see it drop intermittently by the offset amount. I have also not seen any evidence that Windows AVX use is causing the feared 25 to 30% voltage or big temp spikes on my rig, so I created an OC profile for XP with zero AVX offset. For now at least, I don't run other apps on that rig, so I'm not too worried about spikes. However, if I decide to do some 4K video rendering on that PC for whatever reason, then I will make a profile with a -2 or -3 offset. It does make a difference. On my binned/delidded 8700K at 5.3, Windows AVX was causing measurable FPS drops when it kicked in and dropped the freq by the offset amount.

Earlier this year, a number of people who bought binned chips guaranteed at a given clock speed were complaining that they were seeing random drops in clocks well below the advertised speed, even though they had set everything to run flat out 100% of the time. Turns out, they (including me) were all following the binners' advice about the -2 or -3 offset, and that is the exact amount the clocks were dropping. The drops were caused by the offset by Windows. That's straight from the horse's mouth (two of the best known binners). Nevertheless, it's still something to keep an eye on for sure.

 

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Can be that, anyway have no problems with this on Asus Z370 Apex

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I finally found the problem related to what I was complaining "Windows AVX was causing measurable FPS drops when it kicked in". Actually there is recent windows update that is creating CPU SPEED fluctuations based on AVX coding inside windows overriding MotherBoard settings.

Unfortunately I wasn't able to find which update is, I used recovery option on Settings and it did not say which update was rolled back to. 

Now the CPU Speed is steady as a rock, no fluctuations at all in any conditions.

Now I turned off windows update, who knows what kind of other problems will trigger this.

Maybe somebody knows which recent windows update has incorporated "Windows AVX" coding and how to block that update? 

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Posted (edited)

have Win10 set to not install uppdates but get notfacations, think a get some notes but not installed yet.

no problem for now, 

Thank for the Info, great to now if i start to get the fluctations

Edited by westman

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AVX is an Intel instruction set.

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