I'm sure you've examined your Application Manager area under "running" to see what services are running, thus your use of the task manager.
I'm thinking that your new device probably has a lot of bloatware,, but I'm also wondering if you've checked your syncing apps and widgets such as weather and social networking apps. They may be auto syncing by default and at too frequent of intervals. Check them all, even Gmail/email, news, etc, anything that syncs.
You may end up setting most of them to sync on demand, manually, rather than auto.
Perhaps you have found the problem. I went to Sync Settings and foundeverything checked: App Data, Calendar, Contacts, Gmail, Google Photos, Google Play Book, Google+Auto Back, People details, Picasa Web Albums, Web. I've unchecked them all and will wee what happens. I appreciate your help.