Icon's on the Desktop, no matter how many, is part of the boot process. Files have to be opened to get the graphics. The boot process is NOT a single threaded operation. It co-mingles with other operations during boot. That that require disk access 'share' the access.
I have an Intel i7 quad-core and have umpteen things on my desktop, a Dell Dock, a System tray, Quick start tray, gadgets, etc. I too see some icon's and even occasionally some gadget opening up slowly with the icon's being generic. Once the system completes though all is OK. My desktop DID fill fast once I installed an SSD, but then again, the system boots faster and the disk access times are significantly faster.
Some of this could just be 'normal'.
If the icon's bother you, create desktop folders, like Utilities, Photo programs, Games, etc. and move the desktop icons into them. Should help the booting strain.