I’ve had my D800E for a little over a week, and my usage of memory cards may change. Initially I’ve configured the primary CF card to store NEF and the secondary SD to store JPG. The SD also appears to store video. With my D90 or P7100 I don’t shoot JPG at all, but since the D800E has dual card slots, I might use the SD slot for backups. Since my SD cards are smaller and slower than my only CF card (Sandisk 32GB 600x =90MB/s), I configured the SD to store JPG to shorten the image transfer time. That way, I can show my photos if I come across a computer that can’t read CF cards or NEF files.