Confirm these cards are just fine for 720p continuous. Their write speeds benchmarks in ML test about 40 MB/s (controller limit)
Manufacturer's write speed claim is 45 MB/s, which is true (confirmed on usb 3.0 card reader)
Read more carefully, SanDisk says "Read/Write speeds up to 45MB/s" , yes, the read part does go up to 45MBps, not the write speed, sorry, but the devil is in the details. I own these exact cards and tested them in camera and with USB 3.0 and no such luck, write speeds 30-35 MBps all day long. I do realized different copies vary, but not by that much.
Quote from SanDisk site:
http://www.sandisk.com/products/memory-cards/sd/extreme-uhs-1-45mbs/"45 MB/s Read/Write Speed for Faster Performance and Downloads
With read speeds as fast as 45MB/s, this card unleashes the full shooting potential of your advanced camera or DSLR."
Note how at first they combine the statement about 'Read/Write speeds of up to 45Mbps', then they qualify that statement by saying 'With read speeds of up to 45 MBps...', the they NEVER mention write speeds again, only as a combined statement with Read Speeds, subtle, but meaningful legal difference (to avoid lawsuits for false advertising).
This is common advertising gimmick to trick the consumer into 'believing' what they wish were true, but really in fact isn't.
UPDATE: I just re-tested my 45MBps SanDisk 16GB cards, in camera and USB 3.0 card reader, my results:
USB 3.0 card reader: 43.9 MBps Read / 37.5 MBps Write
In Camera: Read 41.7-43.5 MBps / Write 35.7-37.5 MBps
So, my apologies, I don't remember getting this high of write speeds, BUT I do know they did NOT work for continuous 720p@24fps RAW in my camera with FRAME SKIPPING=OFF.