Since buying the DR650S-2CH I have only used my Laptop Card Reader Slot and an SD/MicroSD Converter (see below).
However, this arrangement is USB 2.0 with a maximum speed of (64 megabytes per second, or 480 megabits per second).
Last week I decided to buy a cheap USB 3.0 Multi Card Reader (640 megabytes per second, or 5 gigabits per second), that should be ten times faster!
I am now running it from one of my PC's USB 3.0 Ports (although the new card reader can still run successfully from a USB 2.0 port, but much slower of course).
The functional improvement in the Blackvue PC Viewer is remarkable. The video is smoother and the location map tracking is now completely in sync with the video. The upgrade to 3.0 USB has been well worthwhile. Maybe this approach can relieve some of the issues reported with the Blackvue PC Viewer?
There are plenty of Multi Card Readers available for less than $10 on Amazon, but I can recommend this one for an Asus Laptop. It is made by llano and sold by Zedela. It is reliably recognized by the Asus under Windows 7, it permits card-to-card file transfers (not all readers will do that), and it has storage space for spare cards. You use the 2x MicroSD Card slots in the side for Blackvue Viewer purposes (two yellow Sandisk cards shown in image).