Messed up CPU frequency on Z440

[MysteriousFool]

Hello everyone,

i recently purchased rehabbed Z440 workstation. Everything was going smooth and above my expectation till I messed it up after 2 months (i guess i messed it up). The problem is base CPU core frequency, which has dropped from declared 3,7 GHz to 1,2 GHz and  it is unstable and fluctuating between these values (1,2 - 3,7 GHz).

Suddenly the work is not smooth and fluent at all. When i need some  difficult task (starting an application, boolean difference while modeling, etc.), it always freezes for 2-3 seconds and then it finishes the task quite normally. I use this workstation mainly for Autocad, some 3D modeling and rendering (Rhino+Vray) and i practically can't use it as it freezes several times during a single minute when working in those CAD programs. I basically turned workstation into web browser pc. 

The values which are so wildly fluctuating are: core speed 1,2 - 3,7 GHz, multiplier (12x - 37x) and core voltage 0,7 - 1,1 V. I noticed, that multiplier was on stable value of 37x before this all occurred. I confess I might messed up something in BIOS settings as i tried to enable some PCIe speed extension settings. I put it this particular one back into default value, but it might changed other settings. 

What is wrong here? Can I ask You, what particular settings i should check or how to set BIOS properly? 

System configuration: Z440, Intel Xeon E5 1630 v3 3,70 GHz, 4x8 GB DD4 2133 MHz, Nvidia Quadro M4000 8GB, BIOS M60 v2.50, W10 PRO

Thank You for every single response. 

PS: I'm posting this question for the 2nd time, as it was marked as spam before (i havent received any explanation). Please, this is not a spam, im really looking for solution to a problem. Thank You. 

[JJOcean]

When you say you may have messed it up, did you install a program or make changes that may have caused the problem? This web page may help. Also run an anti virus scan on the system. Did you install another anti virus program as some of them can really affect system performance.

[MysteriousFool]

Thank you for response. I use Avast Premium Security as antivirus program. I ran the scan of the system and it is clear. I installed it several weeks ago, so it shouldn't relate with this problem. 

Prior to this performance drop occured i did several things: I installed Intel's Extreme Tuning Utility application and i installed CPUID CPU-Z program into my PC. ( cause I found on this support forum that intel's  Xeon E5 16xx V3  cpu serie is opened for overclocking, it was not the case of my cpu as i found later). I used both apps only for monitoring my PC performance. I did not change any settings. The only setting i changed was in BIOS. I enabled "PCIe performance mode" - configures power and performance options to maximize PCIe bandwidth (=BIOS description). Warning window popped up saying some various different other settings of PC gonna change due to this. I'm not sure 100%, but it has been after this change when i've noticed the performance drop. I disable the "PCIe performance mode" back again but i doubt BIOS returned the other settings which was related to this one before.  That's why I think I messed it up. 

I tried to put all power and performance setting to maximum in Windows, but i don't see any significant change. Perhaps i should check some BIOS settings, but I don't understand it properly. 

[JJOcean]

There have been some users seeing problems with PC performance with Avast. This page has more information. You could try uninstalling it to see if it makes a difference. And not to worry about a virus problem if you do. MS Windows anti virus works very well and is highly rated in it's latest version. Also check the BIOS for a setting to reset the BIOS to default settings. That should return it to the prior status before you enabled Performance Mode. Also this forum post may help as well. As this also may help though it is from another manufacturer's page. And this pertains to Windows settings.

[MysteriousFool]

Thank You for links and help, JJOcean. It looks like problem is finally SOLVED!

I checked the Windows power management again and it was all right. Making some changes in windows registry was too much complicated for me and it seemed tricky (there was one manual in those links). 

So i restored BIOS into factory setting. It helped a lot. But still the frequency and performance were not stable, however core speed were fluctuating between 2,1 - 3,6 GHz. So I made another two changes in BIOS: "idle power settings" from enhanced > normal and "enhanced halt state (c1e)" from enable > disable. 

I'm not sure, what have I exactly done, I will look it up (hopefully, this change won't negatively involve the system). But the voltage in CPU is stable as well as the core frequency (3,7 HHz). it might be not the most green system setup, but the response of the system and working flow is very nice and much better in comparison with previous situations. Thank you very much for the help again.

The only thing is CPU turbo boost, which doesn't work. But it didn't work even before the performance drop and the boost itself run on 3,8 GHz frequency, which is only 100 MHz more than basic speed, so not much of difference.

[JJOcean]

Glad to hear it! I hope that I was of some help. Take care!