I noticed when my one cloud was syncing, and was dloading heavy to my device (802.11AC and running about 50Mbps) the fan would kick on and CPU use would be 80-100%. should it be like that?
Probably. I'm seeing the same thing syncing IMAP on desktops. Syncing will do that if there is a lot to sync. Syncing is actually a multi step process of looking at everything on both sides to see if anything needs to come or go. There's more going on then most people realize.
So once its synced, it shouldn't need to do that everytime, right? I don't have my charger and it went from 94%-75% and still syncing the IMAP apple account in outlook. I'll probably stay out of Outlook till I get home.
Normally it would only do a complete sync if you made a major change like moving a folder or a large number of files - or an account change. Once it has caught up it shouldn't be a big issue going forward.
I just ran into this with a customer and his system will take hours to fully sync the first time, over 10GB.