>>Personally, I think a 36mp monster like the D800 >absolutely >>needs the best and fastest cards in order to prevent the >>camera from drawing unnecessary attention - to prevent it >from >>distracting us. > >No, it does not for me. I have and tried 133x and 600x. The >way I shoot does not make any difference. The only burst I >have ever used was 2fps once in a blue moon.
I suggest forgetting about 133X, 600X and other speed ratings of this kind. Those ratings, just like the MB/s maximum ratings for any card of any kind from any brand, are the maximum read speeds. It's the continuous write speed that's most important when actually shooting. For the D800, in my experience, anything slower than a rated 45MB/s write speed (SD or CF) can slow down the works.
I've tried a wide variety of cards (SD and CF) from Lexar, Sandisk, Kingston, Transcend, Integral and a few others - all class 10 architecture. Basically, my results while street shooting correspond almost exactly with Rob Galbraith's bench test results. So now I use nothing but Sandisk Extreme Pro SD and CF cards in my D800 (because of the warranty, because they're high volume sellers so the dealers are constantly discounting them, and because I've never experienced a Sandisk card failure). I also have a couple of really fast cards from Integral - the UltimaPro models, SDXC and CF - which write at either 45MB/s.
Can't remember if someone brought it up in the thread already, but have you also tried enabling the SD card? Try setting it to write a backup and see what happens. If you already tried it, never mind.
The largest card I use is 16GB - the SD cards I use as primaries. I have several very large, fast, 128GB CF cards that I use with the CF slot set to backup. When I shoot, I never commit anything more than 16GB of shots to any one SD card. Once the card is full, I dump the contents to my laptop, then store the card until I get back home. That makes (including the backup on sometimes several CF cards, depending on the length and extent of a trip) three copies of everything. Doesn't have anything to do with your conundrum, but I thought it might be of interest anyway.
I have a plastic container full of 1, 2, 4, 8 and 16GB older class, 10MB/s (and slower) SD and CF cards. They're useless in my D7000, and many of the slower, larger old CF cards in the container were essentially too slow in my old D700 too. None of them are anywhere near fast enough and most aren't anywhere near large enough for my D800. Just junk now - or nearly junk. My oldest son (a musician and recordist) grabbed a handful some time ago because he can slot them into a selection of digital audio recorders and other gadgets he uses from time to time.