its most likely something loading up while explorer.exe is loading as thats what your desktop is
i dont have your exact board or setup but ive noticed on my formula that the asus programs installed change order on every single boot
sometimes as soon as i boot ai suite is already loaded up
sometimes kaspersky is already loaded up
sometimes neither of those load till last and my desktop is already fully loaded
id say you best bet may be alter which programs start on boot
CoolerMaster HAF 932 Advanced/ Maximus VI Formula/ I7-4770K/Swiftech H320/ Corsair HX850/ G.Skill Trident X (2x8) 16gb 2400MHz/ 2x 840 EVO 120gb(Raid 0)/ WD 1TB HDD (Backup/Storage)/ EVGA GTX 1gb 560 TI/ Asus 12x bluray combo