Hi there. I’m having a similar issue as well.
I open the project and everything is working fine. If I minimize the window and do something else for a bit, that is when the video tends to freeze.
I am using the most up to date version of Premiere CC 2014 (8.1) and do not have any plug-ins such as RG.
Computer Specs:
Windows 7 Pro
Intel Core i7-3770S 3.1 GHz
Nvidea Geforce 210 (driver 340.52)
250GB SSD for boot
Two 3TB HHD set as RAID 0 for storage