Thanks for the info... I had no idea the write rates were so slow. I feel a little deceived actually, having asked Nikon what the fastest card was that the D700 would support was. So I've invested money in a card with super-fast write speeds but an old quill to write with. Not the world’s best analogy I admit.
Would a slower class card (but still >35MB/sec) be written to at the same speed? I wouldn't be surprised if the 90MB/sec figure was an ideal and fastest possible speed achieved under laboratory conditions only; which would mean that say a 40MB/sec card might reach 15MB/sec in normal D700 use. Hope that last bit makes sense.