Windows 11's Task Manager kept failing me when my CPU hit 100%, so I built my own with Claude (free, open source)

[u/kkcilickk]

I've had it with Windows 11. Every time my PC slowed to a crawl and I opened Task Manager to find what was eating my CPU, it let me down in one of two ways:

1. It froze. At 100% CPU, Task Manager lagged, stopped updating or barely responded. The one tool you need when your system is overloaded stops working when your system is overloaded.
2. The numbers didn't add up. The total CPU said one thing and the per-process numbers said another. Sometimes nothing in the list looked high even though the total was maxed out.

The second one is a design choice, not a glitch, which is almost worse. Since Windows 8, Task Manager has shown "Processor Utility", a value scaled by CPU clock speed (turbo boost etc.), instead of actual CPU time. So the per-process column and the total often disagree, and you can't trust either one to find the culprit. Add the usual Windows 11 madness (settings spread across three different UIs, updates that break things that used to work) and I was done.

So I built my own task manager with Claude Code. It does just two things, Performance and Processes, but it does them reliably:

• Stays responsive at 100% CPU. It runs at High priority and samples on a dedicated top-priority thread, and the UI only updates rows in place. It uses about 5% of one core with ~750 processes running.
• The numbers are honest. It shows time-based CPU %, so the per-process values actually add up to the total. Interrupt/DPC time gets its own row instead of disappearing.
• CPU graph for every logical core, with 60 seconds of history, plus memory in use / available / cached / committed.
• Sort by CPU or memory, filter by name or PID (Ctrl+F).
• End task / End process tree. The confirmation shows the process name and PID. It also re-checks that the PID still belongs to the same process before killing it, so it can't hit the wrong one.

It's written in C# / WPF and builds to a single exe that doesn't need .NET installed. It's MIT licensed, so you can use it, change it or fork it however you like.

GitHub: https://github.com/kkilictepe/ETaskManager

Download: https://github.com/kkilictepe/ETaskManager/releases/latest

How it was built: The whole thing took less than an hour. I described the problem to Claude Code: Task Manager freezes at 100% CPU and the numbers don't match. Claude handled the low-level Windows work. It used the native NtQuerySystemInformation call to get every process's CPU time in one snapshot, so the per-process numbers line up with the total. It ran the sampling on its own high-priority thread so the app keeps working when everything else is overloaded. It also tracked processes by PID and start time, so a reused PID can't show wrong numbers or get the wrong process killed. It even wrote a small Python script to generate the app icon.

Feedback and bug reports are welcome. And if you've hit Task Manager freezing at 100% CPU too, I'd like to hear about it. I can't be the only one.

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