Files in System32 and Winsxs folders not backing up
I have recently installed Backup Exec (BE) 2010 R3 on a server that is running Windows Server 2008 R2 Standard x64, we also have another server running BE 2010 R3. The older server is very old and slow and is there just as a spare in case of hardware failure, however, we did used to use it as our main backup server.
Since I started running backups on the new server I found that the backups are smaller than they were when compared to the old backups. I have investigated this and found that the bulk of the files that make up this difference are in the System32 and Winsxs folders. I have compared the amount of data backed up on the new backup job with the amount that was being backed up on the old server and it varies from server to server, but the difference between the backup sizes can be around 20gb.
In a way this is good as it is saving me time on my backups, but I am little concerned as to why BE is doing this, plus I am a little concerned that if it comes to doing a restore that I may not be able to do so properly. As far as I can see every single option on the backup job on the new installation is exactly the same as the old one, so I am not too sure why there is a difference!
Can anyone explain to me why BE is doing this, and also, is it a problem, should I be concerned about it?