why my .net application horribly slow to start after the machine is rebooted?

Question

Does anyone know why it is so horribly slow to start a .net application after the machine is rebooted(i.e cold start) ?

After researching in google I found some clues for speeding it up i.e.

1. Merging assemblies
2. Setting resource language
3. NGEN
4. GAC installation, etc.

Is that all enough to make my .net application faster or anything else is there I am missing ?

Answer 1

Another reason could be Authenticode signed assemblies and no internet connection. See Why are signed assemblies slow to load? and WPF application slow on startup for example.

Answer 2

As others have stated, your computer is probably still loading other applications during the first few minutes after bootup. Your hard disk (one of the slowest components) is busy trying to load those other apps and their respective data.

If you have a second disk on your computer, try installing your app on the second disk. If the second disk is usually idle during this time, I'm thinking that the app will start up much more quickly.

Answer 3

You could use ProcMon from SysInternals to profile your app during startup. This will log all registry/file access with time stamp. It may point you in an area where there's a delay.

Also, when cold booting, does your machine have a lot of disc access? Is your virus scanner doing a full scan at boot?

Answer 4

If you are pulling up a large number of files from the hard drive, then your system hasn't loaded them yet. This could be the reason for the slow start.

Also, if you haven't given your system sufficient time to boot up, it could still be loading other applications at the same time.