Just picked up an ExpressCard34 CF reader for the MBP since carrying around a traditional USB2 reader was getting annoying (damn cable...). So, I decided to do a quick and dirty comparison using a stop watch to time the transfer speed and iStat menus to get peak transfer speed. Not super accurate, but it gives you a good idea. I tossed in the numbers for a USB drive as a reference.

Items used for the test:
SanDisk Extreme II 2GB
Kingston Elite Pro 133x 4GB
Sandisk Cruzer Micro 2GB
Radio Shack/Dazzle USB2 CF reader
<a href="http://www.geeks.com/details.asp?invtid=CL-EXPRESS-CR&cat=NBB">Generic brand Expresscard34 CF reader</a>
72 .CR2 RAW files (totaling 597MB)
Macbook Pro 2.2GHz/3GB/120GB 5400rpm/OSX 10.4.11


USB2 CF card reader (SanDisk Extreme II)
Total time: <b>2:57m</b>
Peak transfer speed: <b>5MB/s</b>

USB2 CF card reader (Kingston Elite Pro 133x)
Total time: <b>4:32m</b>
Peak transfer speed: <b>4.28MB/s</b>

Expresscard34 CF reader (SanDisk Extreme II)
Total time: <b>0:53m</b>
Peak transfer speed: <b>13.41MB/s</b>

Expresscard34 CF reader (Kingston Elite Pro 133x)
Total time: <b>0:25m</b>
Peak transfer speed: <b>30.83MB/s</b>

USB2 Flash drive (Sandisk Cruzer Micro 2GB)
Total time: <b>0:32m</b>
Peak transfer speed: <b>21.02MB/s</b>

The numbers are fairly clear... the Expresscard34 reader was limited by the speed of the CF cards I have. It also shows how fast the ExpressCard is/can be, compared with a normal USB2 reader. The slow performance from the Kingston/USB2 reader combo is possibly a fluke, or just shows how inconsistent USB2 is. Either way, I really can't explain it. A second test showed similar numbers. However, combine the performance of the EC reader with the small, easy to carry form factor, the ExpressCard reader is a heck of a value when performance and cost are factored in, IMHO. Almost a requisite if you have a laptop with an EC slot. Probably better value than Firewire800 readers I was hoping to get.

Hope this information helps someone! :)

I got a SIIG ExpressCard/54 CF adapter from amazon (dell has em for $22) and with my 4GB Kingston Elite Pro card, I was getting 15-17 MB/s download rates.

I've used this adaptor to DL images off these cards onto my home laptop, and the speeds were comparable to my USB reader on my home workstation. Last weekend I used the adaptor to DL images to my work laptop (Dell Lat D620), and it took over 30 minutes to back up a 4GB card!!!

I thought the advantage of using the PCMCIA adaptor was that transfers were limited by system bus speeds. The CF adaptor is nothing more than a pin adaptor.

So a 32 bit adaptor should do the trick?<ul><li><a href="http://www.mydigitaldiscount.com/ProductDetail.jsp?LISTID=8000018E-1179840782">http://www.mydigitaldiscount.com/ProductDetail.jsp?LISTID=8000018E-1179840782</a</li></ul>