As you can see, with my Lexar expresscard CF card reader.
So far I'm do OK on 1920x1080 24p. but I need to cut like 50 frames until the SKIP FRAMES stops.
The 16GB will absolutely slower than this. But I'm not sure whether a 64GB gets better.
(http://ww4.sinaimg.cn/large/5e6d1cf7gw1e5bbfnvja2j20me0o6ads.jpg)