Why is the syncing process taking a long time?

Records are synced in batches. This might take a few moments, depending on the number of contacts you have in your Gmail and Vtiger CRM accounts.
Vtiger CRM syncs 100 records at one go. If there are more records to be synced on either side, a message is displayed on the sync report. By clicking on the Sync Now button, you can complete achieving records on both ends.

To know more about Google Contacts and Calendar, click here.