What's making my disk thrash in Windows XP?

"Download Process Explorer from Microsoft / Sysinternals.

Run it and click view > Select columns. Click on the Process Performance Tab, and select ""I/O Reads"" and ""I/O Writes"".

You can do this from Task manager, but I prefer using Process Explorer.

You can then sort by these columns and see what is doing the most read / writes.

(if using Vista / 7 remember to run as ADMIN (or click file then ""show details for all processes"" which will do this for you)

I tend to find that Dropbox and mesh on a few machines I support seem to run wild with read/write bytes 24/7 so if you use any sycn software, first bet is to look at that, however running this tool should tell you exactly what is wrong.

In addition, you can click on any of the graphs at the top of the screen which brings up a ""System Information"" dialog of historic information. One of the graphs (third one down) is ""I/O Bytes"", Simply hover your mouse over any of the peaks, and it will tell you what is taking up the most resources. - Exactly what you want!"

"In addition to the mentioned Process Explorer, i would try Process Monitor.

With Process Monitor you can watch file activity happen in real time; which file is being read/written, and by what process.

If it's only happening during startup, then it is due to everything being read off the hard-disk as the machine starts up. Use msconfig to do a startup that doesn't involve ""startup items"".
Another culprit during startup is the size of your User or Machine registry hives. Years of programs installing themselves grows the hives. Try creating another user account, log onto that one and see if it's any faster.
Having too many fonts installed can slow Windows' startup (e.g. Photoshop installs hundreds of fonts i know i'll never use).

The common thread is that there's just a lot of I/O happening on startup. Trim what has to be read, defragment so that Windows can take advantage of it's multiple asynchronous I/O requests, or add more RAM so it can cache more."

"As a general bit of advice, take a look at Defragmenting the drive.

(Right-click the Local Disk drive and select ""Properties"" and then the ""Tools"" tab, followed by ""Defragment Now..."".)

Just click on ""Analzye"". The thing to look out for in the report, is large fragmented files. Somoething I've come across a lot is people with fragmented Outlook PST files. They might have a 500Mb PST fragmented into 1000+ bits and when they open Outlook, the disk goes crazy picking up all the pieces."

Procexp is awesome, but you can add disk i/o columns in the task manager. If you're not allowed to install software you can download it from their live site.