Hard drive constantly in use

[nLinked]

My hard drive is constantly doing something. It doesn't really seem to affect performance but I want to know what it's so busy on.

I'm on Vista Ultimate and this doesn't happen on my other Vista PCs, which have the same settings.

Indexing is already complete according to the status. It is not defragmenting either (not even scheduled). There are no 3rd party programs running. It's not my antivirus program either because if I disable real-time protection the HDD is still doing something.

I have only one HDD, it's only 15% full. It's 250 GB and AHCI is enabled in the BIOS. The HDD supports NCQ but I don't know if its in use or whether it is causing it.

Why is my HDD constantly doing something? It happens even when the PC is idle so it can't be page file activity? The system has 3 GB of RAM. Howvere, sometimes when the PC is idle, the HDD stop doing things and becomes normal. As soon as I start some stuff, the HDD won't stop doing something for ages. It's not extreme, it's always lightly doing something.

 

[postmortemIA]

first, Vista uses super fetch to load stuff into RAM, so it is gonna take a while to load it all into 3GB-used by OS... so it will definitely be in use few minutes after boot.

 

[Matthias99]

Also, you can look in the performance monitor (or something in there) to see exactly what is accessing the drive and what files are being read/written. This will be much more informative than asking us to speculate about what it might be.