>I cannot say it only happens when I am spraying, if one can >call 4fps spraying > >I use 400x cards in both SD and CF slots usually set to SD as >main with CF set to overflow.
14-bit, uncompressed or lossless compressed, 36mp NEF files from the D800 can be as large as 75MB each. A series of two or three, short, 4fps bursts, one after the other, can easily generate a dozen or more files - 1GB or more quite quickly. A 400X card usually writes at a maximum of 60 MB/s. So depending on how few seconds pass between bursts. It can take anywhere up to 16 seconds or more to write the files to the card is that situation.