Windows – Understanding Disk Activity View Charts in Resource Monitor

Disk queue length usually means the length (in number of I/O operations) of the queue of pending operations for a given disk. In other words, how many requests have stacked up waiting for the disk drive to be able to service them. As an example, if I can only process one request a second, but I get 6 requests in a given second, then my queue length will initially be 5 (one request is processed immediately, the five remaining must be queued).

For the meanings of the lines by color, look to the left section at the grey bar towards the middle of the top of the screen. It indicates the color and instantaneous value for each of the variables being graphed.

This annoying system pig-out is caused by a Windows Vista mis-feature (piece of crap) called SuperFetch. While the service still exists in Win7 it's been fixed up and doesn't seem to slow me down anymore, although your mileage may vary.

http://en.wikipedia.org/wiki/Windows_Vista_I/O_technologies#SuperFetch

After disabling this crap-fest, from the Services window (type Services into the start menu search box, find Superfetch, stop it then disable it from auto-starting), these freezeups go away. On systems with sufficient RAM and disk-throughput, superfetch results in a net increase in system performance. On my laptop enabling SuperFetch results in periodic freezes of the system where it doesn't respond at all to mouse clicks. I thought I was going crazy, but it was part of the stuff that the people who brought you UAC and other great innovations threw into Vista. I think it's been reworked or scrapped in Win7 so it won't do this.

Update Commenter says he sees this in Win7. I have yet to encounter a problem with Win7 on laptops, but then all my laptops have very high performance 7200 RPM drives or hybrid or solid state drives. I would like to hear in comments from people who have this problem with SuperFetch slowing down a DESKTOP machine with a 7200 RPM conventional drive, or SSD. (I could imagine this happening on a dog of a hard drive with a 5400 RPM spindle rotation speed.)

Update2 Part of the problem with Windows is that it only reports parent process svchost.exe, and you need to read the other answer below that points you to the SysInternals Process Explorer too, which helps you to find out what actual thing inside svcchost.exe (like superfetch or windows update or something else) is actually slowing your machine down.