I took the plunge and installed Darky 10.2.2EE on my SGS. Now it takes a few minutes to boot, when before (stock + voodoo) it took less than a minute.
Is this normal? If not, what can have caused it?
The first time you boot a device after installing a new ROM, or wiping the Dalvik Cache , the OS needs to rebuild the Dalvik Cache. This cache is what is used to launch the applications on the device quicker.
Any time you install a new application or update an application, a dalvik cache for the application is created. When you wipe the cache, this needs to be rebuilt. The more apps you have installed, the longer it will take the first time it boots.
As a good practice, you should clear the dalvik cache when ever you update your ROM.
On top of that, there could be extra boot scripts that will "extend" boot time.