I have a Verizon 4G LTE Broadband Router with an enhanced Wi-Fi signal strength, and I use it to get internet connection for my Surface Pro 4 (i7 CPU /16GB RAM / 256GB SSD model). To avoid updates, I opened the Settings app and set it as metered connection. However, the tablet always has a high CPU usage and the fan spins with louder noise and the Windows 10 system becomes slow, while I could not get rid of this behavior.
I open the Task Manager and notice that the Service Host Locale System SVChost.exe process gets about 50-60% CPU load and it seems to be not closed. The battery also lasts for a short time. The Locale System service is trying to download Window Defender definition update, but stuck at about 90% and then re-starts downloading the related files.
The High CPU usage problem on Surface Pro 4 is caused by the metered connection configure and edge connection. The Windows Update service can not download the signature file of Windows Defender or others completely and failes at some point, and then repeat the same way. To resolve it, you need to connect your tablet or computer to WiFi, go to the Process tab in Task Manager to kill the SVChost.exe process, then let Windows Update search for updates and it will download the Defender signature file then everything works normally.