Why My PC Was Using So Much RAM and CPU When Idle — and How I Fixed It

By Kim Fourteen | Techwise PH
Posted: July 31, 2025

The other day, I noticed something strange. My laptop fans were running like I was rendering a video or playing a game—but I wasn’t doing anything heavy at all. Just a few browser tabs open. No big software in the background.

Curious, I pulled up Task Manager. That’s when I saw it: my CPU was at 30% and RAM usage was over 60%, even when idle. So I did some digging, and here’s how I got things back to normal.

Step 1: Check Task Manager for Clues
Start by pressing Ctrl + Shift + Esc. In Task Manager, click on the Processes tab and sort by CPU and Memory.

Some processes jumped out right away:

SearchIndexer.exe was always active

SysMain (also called Superfetch) was eating up memory

Antimalware Service Executable was unusually busy

Background apps like Teams and Skype were running quietly

These services are normal, but they shouldn’t be this active when you’re not using your PC.

Step 2: Disable SysMain (Superfetch)
This service tries to make your apps load faster, but it can backfire on older or mid-tier systems.

Here’s how to shut it off:

Press Win + R, type services.msc, and hit Enter

Find SysMain in the list

Right-click and hit Stop

Then right-click again > Properties

Set Startup Type to Disabled

Disabling it gave me a quick 10% drop in RAM usage.

Step 3: Cut Down on Startup and Background Programs
I didn’t realize how many apps were silently running until I checked my startup list. A bunch of programs I never actually use were launching every time I booted up. No wonder things felt sluggish.

Here’s what I did:

Opened Settings, clicked on Apps, then Startup

Went through the list and turned off anything that didn’t need to run right away—like Microsoft Teams, Spotify, and a few manufacturer apps I never use

Next, I took care of background activity:

In Settings, I navigated to Privacy, then found the Background apps section

From there, I disabled several apps I haven’t used in months—Cortana, Xbox stuff, Skype, and others

That alone made my system feel lighter and helped cut down memory usage from the start.

Step 4: Tweak Windows Defender So It Doesn’t Interrupt You
Windows Defender is reliable, but I started noticing that it wasn’t always picking the best times to do its thing. There were days when I’d just be checking email or writing a document, and suddenly my CPU would spike for no reason. The fans would kick in, and the laptop would start to feel warm—even though I wasn’t doing anything intense.

It turns out Defender was running background scans at random times. It was helpful, but it also made my system feel slow when I needed it to be quick.

To deal with that, I changed when Defender runs its scans.

I opened the Start Menu and typed in Task Scheduler, then followed this path:
Task Scheduler Library > Microsoft > Windows > Windows Defender.

Once I found Scheduled Scan, I right-clicked it and opened Properties. Under the Triggers tab, I adjusted the scan time to run late at night—when I’m not using the laptop at all.

That small tweak made a noticeable difference. Since then, I haven’t experienced those random slowdowns in the middle of my workday.

Bonus Tip: Disable Widgets and Copilot on Windows 11
If you’re using Windows 11, those new features like Widgets and Copilot look cool—but they quietly eat up system resources in the background.

Since I didn’t really use them, I turned them off:

Right-clicked the Taskbar

Clicked on Taskbar settings

Then switched off Widgets and Copilot

No noticeable loss in features—and my system felt a bit more responsive afterward.

What Changed After These Fixes
After tweaking these settings, my idle CPU dropped to under 5%, and RAM usage went down to around 45%. No more overheating. My laptop boots faster and stays quiet while I work.

Final Thoughts
Sometimes it’s not a single app causing slowdowns—it’s a bunch of little things adding up. These tweaks don’t require any third-party tools, and they really helped me. If your PC feels slower than usual for no reason, give these steps a try.

Got another method that worked for you? I’d love to hear about it—drop a comment or reach out to Techwise PH.

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