Thanks for your question. You asked how you can measure the speed of
your compact flash memory cards. With digital photos becoming larger
and larger, the need to write to a compact flash card quickly is
incredibly important. I found some great information and a solution
for you to try.
First, some background info. According to dpreview.com, many compact
flash cards are now sold with an 'x' rating, similar to how CD-ROM
drives are marketed. Lexar apparently started this designation, with
the 'x' equaling a single speed CD-ROM drive at 150KB per second. As
dpreview states, it is uncertain how Lexar comes to their 'x' rating.
Lexar does not reveal the equipment used to test the card, nor do they
specify whether the 'x' refers to the read or write speed. The folks
at dpreview put together a great collection of various compact flash
media and their performance on their site, and it's worth taking a
look there. They also have some EXTREMELY in depth reviews of various
digital cameras complete with sample shots. It's a great place to
visit. You can see their review at:
Now its on to benchmarking CF cards on our own system. One of my
favorite utilities for PC benchmarking is a program called 'Sandra'
from SiSoftware. Sandra is an amazing collection of benchmarking
utilities that will quickly and easily get you the information you're
looking for from your compact flash cards. You can find Sandra here:
Or you can jump directly to their download page:
The shareware version is adequate for this exercise. Note that this
page will take you to a mirror site to download the software.
Upon installing the program you will be presented with a screen of no
less than 58 different functions! It can look overwhelming at first,
but for this exercise we're only looking for the 'file system
benchmark.' At this point make sure you are only running the Sandra
application, as other programs could throw off your results.
With your CF/PCMCIA card inserted, click on the file system benchmark
icon. Click on the 'Select Drive:' pulldown and select your Compact
Flash card. The test will begin once you click the drive, so now you
can sit back and wait. It may appear that the program is not working
correctly (on my Dell 8200 the progress bar does not appear), but it
is indeed accessing your card. My test of an '8x' Lexar 16 meg card
took approximately 3 to 4 minutes.
After the test is complete, the benchmarking window will change to
show you the results. Your card will be compared to hard disks at the
top, but what we're looking for is further down the list. Scroll down
the results window until you come to the benchmark breakdown
section. Take those numbers and divide them by 150. You will then
come up with the Lexar 'X' rating
On compact flash cards, reading and writing speeds can vary
dramatically. So its important to look at the difference in speed.
On my 8X Lexar card, my read speed was approximately 1046-1083
KB/second, about 200KB short of an 8X rating. Write speed was even
lower, hovering around 965-999 KB/second. You may want to run the
test a few times to get an average.
With a little bit of software, a calculator, and some patience, you
can measure the speed of your compact flash cards. Dont be surprised
if the performance falls below the rating advertised by the
manufacturer. The dpreview.com people suggested using a firewire
based reader, which should give faster results over a 16 bit PCMCIA
card. This could equal a significant performance increase on the
Im in the IT field, so I knew of Sandra coming into researching this
question. Dpreview is one of my favorite digital camera sites, so
they were my first stop in looking up information on various types of
compact flash memory.
Finally, heres one last thing you may find interesting:
How flash memory works from howstuffworks.com:
Thanks, and feel free to ask for clarification if you have any
additional questions or problems!