C: drive busy if mechanical but not if it is a SSD!

Question

Why every logon, C: drive close to 100% busy for a few minutes if it is a mechanical drive but not busy when I cloned it onto a SSD?

Answer 1

Hi P Underland,

Based on your findings that the system performs normally when cloned to an SSD, the behavior is likely related to how mechanical hard drives handle many small read/write operations during Windows startup and normal background activity.

As an additional check, you could monitor disk queue length rather than only disk usage percentage:

1. Press Ctrl + Shift + Esc and open Task Manager.
2. Go to Performance > Disk (C:).
3. Watch for consistently high Response Time values when the system feels slow.
4. If response times remain elevated even during light activity, check the drive manufacturer's diagnostic tool for a more detailed health assessment.

If the mechanical drive is healthy but performance remains noticeably affected, reducing the number of applications that start automatically with Windows can help lower the amount of simultaneous disk access during startup.

I hope this helps clarify the behavior you're seeing. If you can share the HDD model and the response times reported in Task Manager, the community may be able to provide more specific recommendations.

Let me know if you need further assistance, feel free to ask me by clicking "Add Comment" or "Add Answer" if you cannot add comment so your response will be visible. Thanks for your effort.

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Answer 2

Hi, I'm Bernard. I'm happy to help!

Just to confirm, does your computer have two drives? One HDD and one SSD? If I understand correctly, everything works normally when you're using the SSD (or after cloning the HDD to the SSD), but the HDD stays at 100% usage. If that's correct, it could indicate that the HDD is starting to develop a hardware issue or is failing, which can cause high disk usage and slow performance.