strange cpu temperatures when plugged in on optimus V

[Genome]

Hi guys.

I am currently under the belief im getting faulty readings but I would like to see if its also something I may have missed.

I have this Laptop:

Optimus Series: 15.6" Matte Full HD LED Widescreen (1920x1080)
Intel® Core™i7 Quad Core Mobile Processor i7-4700MQ (2.40GHz) 6MB
GTX 765m

I have upgraded it too also have 16 gig of ram and runs on 2 SSD's

So the issue is that when i monitor my temperatures (I use MSI Afterburner and speedfan as a double check) my CPU temp goes crazy when plugged in. When completely idle it sits at about 50C on battery and will rise by only a degree or 2 when plugged in. But as soon as the laptop starts working the temp goes haywire. Its never stable and will bounce around from anywhere between 70 - 95. Its not gradual change either its constantly bouncing every second 5-15 degrees at a time.

I then tried it under load so I installed the witcher 3 and monitored the temps again. The seem to vary anywhere from 85-99 degrees (again not consistant but its not as large in jumps, mostly around the 95 range).

At first I thought it could be something else adding heat to the system (the old HDD I had in there was next to the cpu but I replaced it with an SSD yesterday). I tried playing without the battery in there, after cleaning the fans, making sure the heat sinks arn't loose and changing the power plan a bit.

Then I felt around the laptop and its basically not feeling hot anywhere accept a small spot above where the power cable plugs in. The air pumping out the back doesn't even feel that hot really. Also the GPU temp is fine. it doesn't go over 70 and is in a stable temperature range.

Then I tried removing the power cable see what happens (still with the witcher 3 running). It immediately (0-2 seconds) drops by 20 or so degrees to about 70 and performance of the game stays the same.

Could it simply be false reading caused by heat from the plug socket or something? The laptop feels fine physically and runs just fine as well. It doesn't shut down like it would if it was over heating. And I don't feel like its normal or even possible that a CPU temp could drop 20-25 degrees in 1 second.

Any thoughts would be welcome. Thanks.

 

[Genome]

Incase anyone is interested I worked out the issue.

It seems that when plugged in the cpu was going straight into turbo boost mode. I throttled the cpu to 95% and its temp dropped straight down to the same as on battery.

Might need new thermal paste, maybe the one fan system isn't enough to cool it turbo boosted effectively. Either way throttling it has done the job for what I use the laptop for.

 

[ubuysa]

Incase anyone is interested I worked out the issue.

It seems that when plugged in the cpu was going straight into turbo boost mode. I throttled the cpu to 95% and its temp dropped straight down to the same as on battery.

Might need new thermal paste, maybe the one fan system isn't enough to cool it turbo boosted effectively. Either way throttling it has done the job for what I use the laptop for.

I've never heard of that issue before, I'd be tempted to give PCS a call.

 

[Genome]

Its 2.5 years old and not in warrenty at this point and not my main machine. So its not really worth it. For all I know its been this way for ages as I never really monitored cpu temps on it until the other day, just gpu temps. I only use the thing a few times a year so Just leaving it throttled will do for now.

 

[Scott]

Which version of Windows are you running? I've read of Win7 & Win10 Telemetry issues where, when idling, the OS starts gathering information which causes 100% load on the CPU.

Can you check what is using the processing power using the task manager?

 

[Genome]

Just incase anyone has a similar problem ever here is an update

I finally managed to get round to replacing the thermal paste on the CPU and it has fixed the issue. Temps are now fine when plugged in and in turbo boost. When I looked at the CPU the old paste was not dry but it was rather uneven and very thin in places and thick in others. It had also spread to ourside of the area you should have paste.