Although neither camera is capable of writing to a CF card as quickly as the USB card reader/writer, I was hoping this series of tests would give some indication of the real world performance gain that can be achieved with the high-speed Photo Steno. However, the results were somewhat surprising. In the PowerShot G2, the Photo Steno and Kingston cards both performed near enough the same in both the JPEG and RAW tests, although the results for the Photo Steno are way off the claimed 100X transfer rate.
In the D30 digital SLR, things were worse still, with the Kingston card actually outperforming the high speed Apacer card by some margin. This suggests that there may be a compatibility problem between the Photo Steno and the D30’s CF interface. Read performance in the D30 seemed to be unaffected however, with the Apacer card appearing just as responsive as the Kingston card during general use (for example when viewing images in quick succession on the D30’s LCD screen).
I really did expect the Photo Steno Pro II to perform far better than it did, especially since the Apacer Handy Steno HT203 USB memory key proved to be so blisteringly fast when we tested it. Ultimately, even though this CF card is faster than average, it's not fast enough to justify the cost.
Ignoring the possible compatibility problem with the Canon digital SLR, the Apacer Photo Steno Pro II is only slightly faster than a standard speed CF card. In our real world tests its performance falls considerably short of the claimed 100X transfer rate, even when used in a USB 2.0 card reader/writer. Everyday users of digital cameras are probably better off paying less money for a slower rated card.
According to Apacer, the original Photo Steno Pro II 1GB CompactFlash Card was an engineering sample. A final production version was retested using two different USB2.0 card readers (updated graphs below). The new results do show an improvement, although its performance in our real world tests still falls short of the claimed 100X (15MB/sec) read speed and 80X (13MB/sec) write speed. The second updated graph demonsrates this.