I have a problem in my domain environment with Windows 8 computers. Initial login time for new users is much longer than in Windows XP.

default profile size new profile size creation time of new profile
Windows XP 1,05 MB ~6 MB ~10 sec.
Windows 8 1,36 MB ~70 MB ~200 sec.

How can I speed up first login time? People in my enviornment very often change their computers and need to login very fast using their own login credentials. They also don't store any private data, workstations are only clients to server applications. I'm not using roaming profiles.
I've noticed that a lot of space is taken by the files in these directories:

WebCacheV01.dat [32 MB]
C:\Users\AppData\Local\Microsoft\Windows\Explorer [13 MB]
C:\Users\AppData\Local\Microsoft\Windows\SettingSync\metastore [10 MB]

Is the creation of these files so time-consuming?