One half of the CPU cores operate at 50% utilization unpredictably.
One half of the CPU cores operate at 50% utilization unpredictably.
Initially, I wasn't back at home with my PC, so I had to rely on general observations. It seems like this problem likely relates to the operating system or software settings, especially since it's affecting the second processor. A few months prior, with my R7 5700G, I noticed temperatures were slightly higher during idle than usual—just a bit above normal. Checking Core Temp revealed that about half of the cores were only around 50% usage. When I opened Task Manager, the cores dropped back down quickly, but they stayed low afterward. This pattern repeated regularly, sometimes multiple times an hour.
At first, it wasn't alarming because the APU design and low TDP made it manageable. But after upgrading to AM5 and using an R9 7900X, the heat output nearly doubled. Now I have an Arctic LF3 360 AIO and an ROG ROG Strix 360, both showing similar issues—around half the cores at 50% load. The motherboard clock speed often stays stuck near 5 GHz, which adds to the warmth.
Living in Texas with hot weather has made this even more noticeable. My ceiling fan isn’t working well, and the desk fan runs nonstop. I do keep the PC running almost nonstop, but I’m planning a clean install soon. This will help remove old files, drivers, and lingering software that might be causing the problem. I’ll update my notes once I’m back home with more detailed images.
Avoid shutting down the task manager. Maintain the window sorted by CPU load and temperature. Show both at once. When CPU usage rises, identify the source of the increase. If no changes occur, keep the computer running with the manager open indefinitely, though this may not always be practical
Well, whether it's running for a computer in technical jargon or not, it's just as inactive as it can be for what I'm doing with it. Still shouldn't be causing this problem, I think it should hover between 5-20% across a few cores like my laptop does—though the exact setup is different in terms of processors, but it’s close enough. Yeah, I remember some of the extra tests I ran. When I had the 5700G, I kept the Task Manager open for a couple of hours, and apparently the issue never showed up. I also recall with the Corsair Link H150i, I could spot the problem right away—fans would spin non-stop, core temps spiked, and after a moment they slowed down. That screenshot I mentioned was taken when I installed the AIO; temperatures hit the 90s, so I thought the pump might be bad. I sent it back and got the LF3 instead. Anyway, I’ll do more testing to see what temporary fix works, check if a Windows reinstall helps, and keep track of what I install just in case it comes up again. Leaving Task Manager open could work, but I’d need to hide priority windows (whatever they are) and maybe move it to another monitor—definitely doable.
It doesn't matter as long as there are a few active programs with some activity in certain cores. The challenge lies in understanding frequency, intensity, and quantity. That's more difficult to assess. If you can't identify it immediately, it increases the chance it's a background process (like antivirus or updates) consuming your time, even though you think you're using the system actively (such as opening Task Manager). Technically, your computer always runs something, so decisions about what counts as "idling" involve some processing. Similar inconsistencies appear with screensavers or sleep modes. Ideally, you'd like to pinpoint the cause so you can choose whether to tolerate it. I'm unsure if any hidden program can accurately report background CPU usage without being detected by Task Manager.
Ended up pulling an all-nighter, kept task manager open but minimized the whole time, was mostly just window shopping, didn't play any games, average temp was in the low 50's, didn't feel a warm breeze on the top of the case (top mounted rad). Yeah, it didn't do the 50% thing, so I figure this'll be the farmer's fix (can't remember the exact phrase, but temporary fix working good enough it's now permanent) till I reinstall windows, just need to remember to not close task manager.