Thanks Richard for that info. I would have thought that the D300 manual on the Nikon website would have been updated but as you say it is not either.
So, I believe my card reader ( Lexar Prof UDMA USB 2.0 Dual-slot)is the limiting factor here when considering card speed (eg. 300x speed). The reader transfers to computer at 40MB/sec. How does this transfer speed relate to card speed? What speed is above the capability of the reader I have?
What I'm asking is (eg.Lexar 300x vs Lexar 1000x)what is the highest speed card I can buy that will utilize the 40MB transfer speed economically-