Why is my 6700K CPU's speed lowering to 1.75ghz under load?

[asdfguy]

I have a 6700K (not overclocked) with Corsair H55 water cooling and, when I render a video, the CPU speed drops to 1.75Ghz after a couple of minutes. It will render at full 4Ghz then drop to 1.75Ghz and bounce back up again to 4Ghz. I checked the CPU temperature using HWMonitor and it doesn't go over 55c

I have tried re-applying the thermal paste but it didn't. I reset and updated the BIOS and it still didn't help. I tried using a Cooler Master Hyper 212 EVO Fan CPU cooler and it still didn't help.



What could be causing this?

This is my PC specs:

CPU: intel 6700k (not overclocked)
Motherboard: Gigabyte GA-B150N Phoenix-WIFI Mini ITX
Thermal paste remover: Arctic Silver ArctiClean Thermal Material Cleanser (60 ml)
Thermal Paste: ARCTIC MX-2
RAM: HyperX16GB (2X8GB)
GPU: Zotac Nividia 1060 6GB Mini (Not Overclocked)
SSD: Samsung 850 Evo 128GB
HDD: Toshiba 2TB HDD
PSU: Be quiet! Pure Power 10 600W

 

[Meaker]

Use a program like XTU that can give you throttle reasons.

 

[ScoTTyBEEE]

Throttlestop is another good one.

 

[tamzzy]

What could be causing this?

Motherboard: Gigabyte GA-B150N Phoenix-WIFI Mini ITX

Lack of good vrms/vrm cooling = throttling as the vrms overheat

 

[Robin Gregg]

First thoughts are adequate Cooling? is the heatsink compound applied evenly?

 

[DarrenM343]

Did u buy it new? Are u sure the rendering software is applying consistent load? Maybe use something like prime to apply load to mem and cpu for a 10 min period and see how it behaves

 

[Phixsator]

Lack of good vrms/vrm cooling = throttling as the vrms overheat

^-- I'm with this guy. Considering you are using an AIO and not a normal air cooler and you must likely get next to no air over the already limited VRM setup, I would investigate this issue first and see if some extra airflow could help with the problem. Perhaps try temporary fan that blows air straight over the vrms and see if it resolves your issue.

 

[SirCanealot]

^-- I'm with this guy. Considering you are using an AIO and not a normal air cooler and you must likely get next to no air over the already limited VRM setup, I would investigate this issue first and see if some extra airflow could help with the problem. Perhaps try temporary fan that blows air straight over the vrms and see if it resolves your issue.

Might have to agree too. I have a 6600k in a mini ITX board. While it's happy to play games all day at 4.4ghz with pretty low temps, if I actually try and stress test 4.4ghz I'll get similar drops with pretty low CPU temps.
I think I have to drop it back to around 4-4.2 to get it to stress test without throttling.

Would be interesting to know if a fan fixes the issue or not

 

[ZXSpectrum]

I have had some really significant problems with Gigabyte ITX Motherboards and VRM cooling. Put a fan over the VRM cooler and see if it still does it.

 

[ZXSpectrum]

LOL Maybe I should have not skim read the other comments..