Blender starts significantly slower than on my Linux machine. On the latter it’s pretty much instant, while on Windows I’m spending like 15seconds staring at a completely gray window before the start-up scene etc appears.
Obviously add-ons like Animation Nodes or Box cutter elong this whole spiel, but even vanilla Blender starts verrrrrry slowly on Windows.
Starts under 2s for me, perhaps you trying to open Blender while other processes uses system resources?
Any networked drives involved?
IIRC there was an issue with files from the Recently Opened list being on inaccessible networked drives.
Are you using Windows 10? Every now and then after OS startup Blender and other apps take longer time to start for first time (10 sec for blender). After that consecutive apps startups goes normally (2 sec).
I think this is completely related to Windows and blender devs probably can’t change that.