Did you click the links...specifically,
this one?
Yeah, I did.
The equivalent page in the D90 manual is page 262, and it says,
The following table shows the approximate number of pictures that can be stored on a 2 GB Panasonic Pro HIGH SPEED card at different image quality and size settings.
Your reply to jdeg referred to the D5000 and the card for that table was a "30MB/s" card. That's the speed of the card, but doesn't say what the speed of the camera is.
(OBTW, the Panasonic card used for the D90 table is rated at 20MB/s. I wouldn't think the SPEED of the card would affect the capacity, BWTHDIK.
Another goofy issue is the "class rating" of a card doesn't consistently follow the "MB/s" shown for the card. One manufacturer says a card is 30 MB/s and Class 6, while another has a card that is 20 MB/s and Class 10.
And they ask me why I drink.)
Your blog post
The Definitive Guide to SD Memory Cards states,
...the highest speed rating your camera can handle. For the Nikon D90, this is 30MB/s.
My question remains, where did this information come from?
Also, see some official testing results
here.
Okay, getting closer - some empirical data.
The highest observed transfer speed was 20.1 MB/s on a card rated at 30 MB/s.
(As side note: To truly illustrate the case where the card limits the speed of transfer, the author should have shown the rated speed of each of the cards used and included testing for cards with rates that actually exceed the camera's capability. Maybe he did, but we don't know that without the card speeds. That doesn't relate to my question, however.)
dpreview.com tested the file "flush" rate with both 30MB/s and 20MB/s cards and
estimated over 6 MB/s for RAW images with the cards used. That's quite a difference from the 20.1 MB/s observed in the other tests. Obviously, there's an orange is someone's apple crate.
I hope I'm more clear. I see where you said the D90 transfer rate was 30 MB/s, where someone tested it up to 20.1 MB/s, and where someone else estimated it at over 6 MB/s.
Is there anywhere that Nikon has published the actual maximum camera transfer rates?