i7 6700 Power limited

[Fly14]

I have an old Fujitsu office pc with an Intel i7 6700. I noticed a long time ago that when playing games heavy on the cpu, the core clock dropped from the 3.7ghz turbo to the base 3.4ghz and sometimes even lower to 3.3-3.2 GHz. I recently discovered throttlestop and I was amazed when I found out I could simply change the power limits on my old locked CPU. I raised pl1 and pl2 and saw that to avoid power throttling, the CPU uses about 90w, but now holds 3.7ghz. The CPU had a default PL1=65w (TDP) and PL2=81w.
To me it seems strange that it uses that much power. Do you think my cpu has a normal behaviour? Will I do harm if I raise the power limits?
Thank you in advance

 

[eidairaman1]

Turbo is an upto speed which it will vary, the tdp average is 65 w but that is typically for the heatsink solution used, so with that it is common and normal for thermals to go up as clocks go up.

Example my FX 8350 is 4.2 Stock and gets up to 4.7 Turbo and its tdp is a 125W chip, well I have it at 5.0 with no variable clock ramping enabled so its TDP would be akin to what a FX 9370 or FX 9550 would be.

Bear in mind that fujitsu probably uses the stock retail boxed intel cooler which is going to produce more noise due to reving higher to keep temperatures in check than a 120mm fan based heatsink.

The question you should be asking is can that oem motherboard support 81W tdp or more?

 

[Lew Zealand]

Another thing to consider is: can you undervolt your CPU as the Mobo may be feeding it too much voltage? Very likely it's working at a safe voltage for long term use but still more than it needs.

I have a Dell Precision 3620 (I think) with an i7-6700K I added afterwards but I can't undervolt it as it's BIOS was updated to prevent that (Plundervolt vulnerability) before I got it, but I wish I could. As a better binned part than yours, it uses only a max of 70W during all but the most demanding workoads, which is why IMO your CPU could use a bit less voltage. But that undervolt option may very well be limited by your motherboard like mine.

 

[unclewebb]

Will I do harm if I raise the power limits?

Not likely.

You are using a 9 year old processor. It could die tomorrow or it could last another 9 years whether you increase the power limits or leave them as is. The 6700 and 6700K both came down the same assembly line. Intel unlocked the multiplier and increased the power limits and put the good CPUs into 6700K boxes while the not so good CPUs were sold as regular 6700 CPUs. Your processor is not self aware. It does not know what power limits it should be set to. I would increase both turbo power limits to a minimum of 90W and likely a lot higher. Let your CPU enjoy its golden years as it tries to run like a 6700K.

I was amazed when I found out I could simply change the power limits on my old locked CPU.

Locked only refers to the maximum multiplier. You cannot increase the multiplier and overclock a 6700. Intel and most manufacturers left the turbo power limits unlocked so you can set these however you like. If Intel thought this was going to be a problem, they would have locked both the multiplier and the power limits but they didn't.

Post a picture of the FIVR window. There might be a few more adjustments available that are not locked.

 

[PHVM_BR]

I have a Dell Precision 3620 (I think) with an i7-6700K I added afterwards but I can't undervolt it as it's BIOS was updated to prevent that (Plundervolt vulnerability) before I got it, but I wish I could.

Try selecting the Factory Defaults option in the BIOS.

If your tower came from the factory with undervolt unlocked this will make undervolt possible again.

 

[Fly14]

Thank you for your replies!
This is a picture of the FIVR window while stressing the CPU and also a picture of the TPL settings.

 

[unclewebb]

Your CPU is running fully loaded at its full rated speed. Zero throttling. Temperatures are great so there is no reason to undervolt or do anything else. Enjoy your retro CPU. Kind of nice having a CPU that does not run at 99C like many newer Intel CPUs like to run at.

 

[Lew Zealand]

Try selecting the Factory Defaults option in the BIOS.

If your tower came from the factory with undervolt unlocked this will make undervolt possible again.

Thank you! I had come across this somewhere recently but forgotten what specifically to do.

 

[Fly14]

I tried undervolting the cpu, 100mV seems stable (also 125, only 150 crashed) and now it's using way less power!
Do I have other settings to modify to improve the system?

 

[unclewebb]

and now it's using way less power!

That was easy! Move a couple of sliders in ThrottleStop and power consumption dropped over 20%. No need for more nuclear reactors. Just need more people to install ThrottleStop. That would make a data center owner happy.

Your computer is running great. No need to do anything else.

 

[Lew Zealand]

Try selecting the Factory Defaults option in the BIOS.

If your tower came from the factory with undervolt unlocked this will make undervolt possible again.

Apologies for the necro but I wanted to emphasize doing this on Dell Optiplexes, Precisions, Latitudes from at least 8th gen and earlier if undervolting is locked, as I finally found and did this on my Precision 3620. Already did on an Optiplex 9020 (4th gen) and laptop Latitude 7490 (8th gen).

Now my 6700K with borrowed 88W cooler from a 4790 (the Precision shipped with a 65W i5-6600* and smaller cooler) in another Opti9020 can run under 80C, which allows the BIOS to keep the CPU at 4GHz all-core. When it'd hit 80C before, it'll dip to 3.8. It ain't much but at the low end, every little bit of performance is appreciated!

* Seriously. Someone specced out a Precision with an i5. Not an Optiplex. But I'll take it as it has a full size PSU where the MT Optis of this gen only got the same non-standard teeny PSUs from the SFF models.