Taken from Rob Galbraith online:
"This card, which began to ship in mid-March 2004, contains faster memory than the original 40X card. Lexar has revamped their entire 40X Pro Series lineup, from 256MB to 4GB, with the faster memory, though we've only tested the 1GB model. The packaging for the revamped 40X doesn't indicate that the card inside is different from an original 40X, though the card itself does: if the series number stamped on the card's edge ends in C977, it's a revamped 40X."
Frankly, I'm not sure whether he's referring to the silver one... :dunno: but the write speed improvement (NEF file) on my D100 over the Transcend 30x is noticeable.