In our testing of 1GB Ultra II and 1GB Extreme CompactFlash cards, write speed does in fact click past the 9MB/sec mark with several common Windows benchmarking utilities. Actual throughput in a range of digital SLR cameras is much lower, however, as it is for all cards that push the upper limits of today's CompactFlash technology. Even with the cameras themselves putting the brakes on, however, Sandisk's Ultra II and Extreme are the quickest in all current Canon digital SLR models and the Fujifilm FinePix S2 Pro.
Write Acceleration (WA) technology keeps Lexar's best firmly in the lead in the Nikon D1X and D1H, both of which support Lexar's enhanced camera-card communication protocol. WA support isn't enough to completely overcome the raw speed of Sandisk's new flash memory and controller in the Ultra II and Extreme cards in all WA-capable cameras, though. Sandisk's newest performance cards trail the just-released Lexar 1GB 40X WA by less than 2% in the Kodak DCS Pro 14n, and are effectively tied with it in the Nikon D100 (though the Lexar card retains a slight lead in writing NEF format files).
In short, the Sandisk Ultra II and Extreme cards wring about as much write speed performance as possible from today's digital SLR cameras, eclipsing perennial performance leader Lexar in cameras that don't support Write Acceleration, and nipping at the heels of Lexar's speediest offerings even in some of the cameras that do. The Ultra II and Extreme are also quicker across the board than the revamped Ultras, which are being phased out in favour of their higher-performing replacements.