SanDisk Extreme III 4GB SDHC - Performance and Final Thoughts

Article Index
SanDisk Extreme III 4GB SDHC
RescuePRO Software and Testing
Performance and Final Thoughts

Performance Testing & Info:

As we look at performance testing, I simply used HDTach for comparison between a bunch of flash media.  We used the full read/write test on all of the media and averaged the minimum and maximum write speeds per block.  Traditionally, HDTach doesn't display all of this information, but it is available in a CSV file in the program directory.  We used multiple cards - including a 16GB MicroSD card that is a Class 4 device.

All of the cards were plugged into a Lenovo T61 laptop with an integrated card reader for best performance.  There might be faster card readers available, but for this test, all cards were tested on the same laptop.  The MicroSD card was tested in a USB-to-MicroSD adapter.

Finally before we show off individual results, we'll find out what makes the SanDisk Extreme III SD card great - according to SanDisk.

Serious professional photographers who demand one of the fastest, most rugged, and most durable memory cards on the market should choose the SanDisk Extreme III SD card. Built to work under the most challenging conditions, with SanDisk Extreme III you’ll get more speed, better performance, and unmatched reliability.

That’s because only SanDisk Extreme III memory cards feature innovative ESP Technology for the fastest speeds and highest performance. ESP stands for “Enhanced Super-Parallel Processing”. Simply put, it means you are getting the fastest read/write speeds available – an amazing minimum 20MB per second** sequential read and write speed – speed you’ll definitely appreciate whenever you find yourself shooting and storing pictures in harsh environments, extreme temperatures or at high altitudes.


For a straight one-to-one comparison, we take a 4GB OCZ 150x flash card and put it up against the SanDisk Extreme III.

HDTach - OCZ 150x
HDTach - OCZ 150x

The performance of both cards is pretty good, but the SanDisk Extreme III edges out the OCZ 150x card by a hair in the read test, and increases the lead in the write test - which is more important when it comes to DSLR usage.  Both cards manage to read back data at over 22MB/sec average, but the OCZ card drops off to 15.5MB/sec write speed while the SanDisk card bests it by 4MB/sec coming in at 19.5MB/sec.

Below is a chart that shows how all of our tested flash media compares.

Flash Performance


We tested a 2GB Eye-Fi card, a 4GB OCZ 150x SD card along with the 4GB SanDisk Extreme III card.  We also dropped in a couple of 16GB candidates - a Patriot Class 6 SDHC card as well as the 16GB SanDisk Class 4 MicroSD card.  It's interesting to see that the MicroSD card owns the Eye-Fi card in both read and write tests.  Eye-Fi has the slowest performing card of the bunch.


Final Thoughts:

At first glance the price tag of SanDisk Extreme III SD cards may turn some people off, and certainly in these tighter economic times, a cheaper card can certainly be a lot more attractive.  You must keep in mind though that these other cards are indeed "cheaper".   The price tag is lower on other cards and the quality is questionable.  I bought a new 16GB Patriot Class 6 SDHC card to take to CES and the second day out my card corrupted and I had to swap in a smaller card.  I've also had compatibility issues with some cameras and the OCZ 4GB 150x card, as it is has the capacity of an SDHC card, but in fact is not a "HC" card - only and "SD".  I have had no issues with the SanDisk Extreme III card and the performance is second to none.  Combine that with handy RescuePRO software - which retails for $40 and you've suddenly bought yourself a ~$15 card which isn't too bad at all.

Apples-to-apples, SanDisk wins based on performance and features.  However, if you're on a tight budget and don't need or want the handy RescuePRO software, you'll probably be much happier saving your money and grabbing an $11 4GB Patriot Card - just pray that it doesn't corrupt - or you'll want the software.



  • Comes with bundled RescuePRO Software
  • Fast read/write speeds



  • Couldn't hit 30MB/sec
  • More expensive than competition



 Editor's Choice

While the 4GB SanDisk Extreme III earns our Editor's Choice award, they could still make the bundle better by including a USB-to-SDHC reader for those that have a slower reader or have a laptop without a media card slot.  This would increase the value of the bundle.

I'd like to thanks SanDisk for sending this card our way for a review.  If you have any questions or comments, please post them at the "Comments" link below.