The startup priority in Windows is as follows, listed from first to start to last to start:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Runonce
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\Explorer\Run
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\Windows\Run
HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\RunOnce
SystemDrive\Documents and Settings\All Users\Start Menu\Programs\Startup
SystemDrive\Documents and Settings\username\Start Menu\Programs\Startup
The last two items relate to Windows XP days. Which relate to %PROGRAMDATA%\Microsoft\Windows\Start Menu\Programs\Startup
And yes, to answer your question, Windows Vista, 7, 8, and 10 use the same startup folder.
So, if you want your program to run first, always use: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
Otherwise, the startup folder, will load after everything else is loaded.