How to Check Which Programs Are Slowing Down Your PC

Task Manager's Processes Tab Is the Starting Point

Press Ctrl+Shift+Esc to open Task Manager, and you'll land on the Processes tab by default — a live list of every running app and background process, each with its own CPU, Memory, Disk, and Network usage columns. Click any column header to sort by it, and the biggest resource consumer for that category rises to the top immediately.

This single view answers the question for most people most of the time: whatever's sitting at the top when sorted by CPU or Memory is very likely your actual bottleneck, not a guess.

It's worth resisting the temptation to jump straight to ending tasks based on a single glance, though — a process that briefly spikes to the top of the list isn't necessarily a problem, and closing something you don't recognize on sight can interrupt work you didn't realize it was doing. The goal of this first look is orientation, not immediate action.

Sort by Each Resource Column in Turn

1. Open Task Manager and go to Processes.

   Press Ctrl+Shift+Esc, or right-click the Start button.

2. Click the CPU column header.

   Sorts processes from highest to lowest CPU usage — click again to reverse the order.

3. Repeat for Memory, Disk, and Network.

   A slow PC can be bottlenecked by any one of these, so checking all four rather than just CPU catches problems CPU alone would miss.

Use Resource Monitor for More Detail

When Task Manager's summary isn't enough — for example, when Disk usage is high but you need to know exactly which file a process is reading or writing — Resource Monitor provides a deeper, more granular view.

1. Open Resource Monitor.

   Search "Resource Monitor" in the Start menu, or click "Open Resource Monitor" at the bottom of Task Manager's Performance tab.

2. Check the Disk tab for specific file activity.

   Shows exactly which files each process is reading or writing in real time — useful for identifying a runaway backup or sync process.

3. Check the Network tab for bandwidth-heavy processes.

   Shows send/receive rates per process, useful for catching an app quietly using significant bandwidth in the background.

Check Background Processes, Not Just Apps

Task Manager's Processes tab separates entries into Apps (things you can see with a window open) and Background processes (services and helper processes running without a visible window). It's easy to focus only on the Apps section since that's what's visible on your desktop, but background processes are frequently the actual source of high resource usage — a cloud sync client indexing files, an update checker running a scan, or a printer utility polling for status, none of which show up as an open window.

1. Scroll down past the Apps section.

   Background processes are typically listed below, still sortable by the same resource columns.

2. Watch for unfamiliar names running high.

   A background process name you don't recognize consuming significant CPU or memory is worth investigating even though it has no visible window.

Windows itself runs a number of legitimate background processes with names that look cryptic at first glance — things related to system indexing, telemetry, and driver management. These aren't usually the cause of a genuine slowdown on their own, but distinguishing them from a genuinely problematic third-party process is exactly why searching an unfamiliar name before acting on it matters more than reacting to the name alone.

Reading the Four Resource Types

What to Do Once You've Found the Culprit

Identifying the process is only half the job — what you do next depends on what it is. If it's an app you recognize and rarely use, closing it (or uninstalling it if it keeps returning) solves the immediate problem. If it's a background service tied to something like antivirus scanning or a Windows Update installing, the high usage is often temporary and resolves on its own once that task finishes. If it's a process you don't recognize by name, a quick search of the exact process name (visible in Task Manager) usually reveals what software it belongs to before you decide whether to act on it.

For a recurring high-usage process you use occasionally but not constantly, disabling it from startup (covered in a separate guide) is usually a better long-term fix than repeatedly ending the task manually each time, since a manual "End task" only lasts until the next time you log in and the process launches again on its own.

Why Does the Same App Sometimes Show Different Usage?

Resource usage for any given app naturally fluctuates based on what it's actively doing at that moment — a browser idling on a static page uses far less CPU than one playing video or running a demanding web app, even though it's the "same" browser process both times. This is why a single snapshot in Task Manager can be misleading; watching usage for thirty seconds to a minute, rather than judging from one instant, gives a much more accurate read on which process is consistently the problem versus which one just had a brief spike.

Browsers deserve a specific mention here, since they're one of the most common sources of confusing Task Manager readings — a browser with many tabs open typically shows up as several separate process entries rather than one, since most modern browsers run each tab (or group of tabs) as its own process for stability. Sorting by memory can make it look like "the same app" is using an unreasonable amount, when it's really the cumulative total of many tabs each using a modest, individually reasonable amount.

Startup Impact and Ongoing Usage Are Different Measurements

It's worth distinguishing between an app's startup impact (covered in Task Manager's separate Startup apps tab) and its ongoing resource usage once running (shown in the Processes tab). An app can have low startup impact but high ongoing usage, or the reverse — a heavy creative app might load slowly at startup but then sit nearly idle when not actively being used, while a lightweight-looking notification app might launch instantly but continuously poll for updates in the background.

Checking both separately, rather than assuming one predicts the other, gives a more complete picture of where a specific app's actual performance cost lies.

Efficiency mode, a Windows 11-specific feature, is worth knowing about here too — right-clicking a process in Task Manager and choosing "Efficiency mode" throttles that process's resource priority without closing it, which is a useful middle ground for a background app you want to keep running but don't want competing for resources with whatever you're actively doing. It's reversible at any time by toggling the same option off.

Startup impact and ongoing resource usage measure two different things — checking both gives the fuller picture.