CPU Temps mystery.

slowpoke · 27 Dec 2023 at 22:28

Hello, smart people.

Here's a riddle for you to solve as i have failed...
Hardware in question is i7-5930K CPU in Asus X99-A, 16gb of DDR4 2133 RAM(4 sticks), RTX2080, 1tb nvme, 128gb sata ssd (boot), 6tb sata spinny storage.
Software: Win10 and for monitoring cpu temps - CoreTemp 1.17.1.

Situation as follows: Start the computer, start coretemp, leave it alone, come back to cpu baking at ~80C idle (cpu repasted ~6months ago, not first rodeo in this). So, logical thing is to check whats chewing on CPU by using task manager, and AS SOON as i start that temps drop to normal 30-35C. Nothing chews at cpu, at least not obviously. And also as long as taskman is running it never goes past 30-35C normal temps (unless i start something CPU intensive). No unusual software autostarts and hangs about while idle. Even at not complete idle (i.e. me watching funny cats on youtube) will trigger temp rise randomly if taskman is not present... Case is open, coolers be spinning, etc.
No device conflicts or yellow exclamation marks, drivers present etc...
And no, i'm not reinstalling windows as some of the ancient software i'm running here is a pain to get started on fresh install...

Its the whole schroedinger cat thing where mere fact of observation influences the outcome... No idea whats going on. So now as soon as i restart i also start taskman to keep temps down...
Any ideas ?

andy_mk3 · 27 Dec 2023 at 22:33

Try HWiNFO64. This will give you CPU utilisation as well as temps. Might help you see what's going on.

andshrew · 28 Dec 2023 at 09:08

The most obvious answer would be you have something trying to evade detection, probably something like a malicious cryptominer.

With task manager closed and the CPU under load you could try getting a process list via PowerShell. Run it as Administrator:

Get-Process | sort CPU -Descending | select -First 10

If you see a suspicious looking process get the command line it has been run with (replacing 1234 with your Id):

Get-CimInstance Win32_Process | where ProcessId -eq 1234 | select CommandLine, Name, ParentProcessId

You could also try Process Explorer. If the same thing happens with that as with Task Manager, you could try renaming it before running it. Whether or not that works will depend on what lengths they're going to in detecting things that are going to help identify the process.

Process Explorer - Sysinternals

Find out what files, registry keys and other objects processes have open, which DLLs they have loaded, and more.

learn.microsoft.com

Murphy · 28 Dec 2023 at 11:18

Probably Task Scheduler running some on idle tasks, basically system maintenance when it's not being used.

My guess is if you opened a powershell window and typed 'Get-ScheduledTask | Where-Object { $_.State -ne "Disabled" -and $_.Triggers -match "MSFT_TaskIdleTrigger"} | Get-ScheduledTaskInfo' you'd probably get a longish list of tasks with a last run time from a few seconds/minutes before the system stopped being 'idle'.

If it is that then typically things die down a bit after they've done their thing, stuff like defragging HDD only kicks off once a week on idle, other stuff a single time after a fresh install, and some once a day.