Question Laptop hard drive almost permanently spinning and never idle


Feb 20, 2003
The internal hard drive on my Thinkpad T520 is spinning virtually all the time and never stops. I have the power settings set to turn it off (go idle) after 1 minute but that makes no difference.

It spins completely 100% all the time if I am web surfing (visiting many sites quickly; sites may have ads, video etc) or using photo software or watching video. It cycles on and off at random intervals ranging from about 10 to 90 seconds if I have no programs open and am not touching the computer at all; same if I am doing lightweight things like reading one web page that doesn't have ads and not clicking around, or typing in a text-only Word document. There is never a time when it is idle for more than about 90 seconds.

I always thought hard drives generally stop spinning when they're not obviously in use for saving files and occasional behind-the-scenes activity by the OS (or rather, after a minute/couple of minutes of non-use). Is that correct?

We know the problem is the computer and not the drive itself because the spinning will behave properly (stops when idle; can be manually stopped with HDDScan) if I take it out, put it in a USB-connected external enclosure, and install a different HDD (with Windows on it) internally in the laptop.

If I swap the two drives, whichever one is internal will have the near-constant spin and whichever is external will display proper normal spindown.

I can see the disk activity in Resource Monitor but I don't know what is normal and what's abnormal. Under 'Processes with Disk Activity', System and svchost.exe are always there and writing (about 9,000 B/sec and 9 B/sec respectively) even with no programs open. Is that OK? Programs such as Firefox, MS Word or Windows Explorer come and go from Disk Activity depending on whether I am clicking in Firefox, saving the Word document, etc.

CPU use is 0 to 2% in low-load situations (Word, simpler websites), 20-50% with complicated websites, 100% on websites with tons of video and animation. It does not go up and down in relation to the HDD spinning.
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