Larger and Cheaper. But Faster?

I just can't help myself. SD Cards are getting larger in capacity, all the while the price is dropping lower and lower. So when Fry's Electronics was advertising a PQI 8GB SDHC Card for sale, I took the bait.

The PQI 8GB SDHC card advertise itself as being a Class 6 card on the package itself. Classification number is a new speed rating system for SDHC cards, but they seem to be an over simplified explaination. Class 6 should be as fast as cards such as the SanDisk Extreme III line of cards. In fact, you can check out the SanDisk 2 GB Extreme III card tested here.

So what are the class ratings? With SDHC cards, the SD Association created 3 classes to help customers find out how fast their SDHC card can write just by the class rating on the package. Here are the classes:

Class 2 - 2 MB/s or higher
Class 4 - 4 MB/s or higher
Class 6 - 6 MB/s or higher

What they mean by "or higher" is that a Class 2 card, for example, will be no faster than 4 MB/sec. This means that a Class 6 card can actually be much much faster than 6 MB/sec on writes. So when you find a Class 6 card, you can be sure that it won't write slower than 6 MB/sec, but you won't be sure how fast it really can go without benchmarking it yourself.

Packaging
PQI, as usual, packaged their 2GB card in a snap-together plastic mold. It's all too easy to open up the packaging, so normally they are stapled as well to keep from thevies (yea... very secure...). The card comes with a plastic SD card holder, but really nothing else. Don't really need anything else, really.

Performance
In informal tests, my Canon Powershot A640 10 MP camera was able to take pictures in succession in the highest quality without any lag or waiting for the last picture to write. Each photo was around 3 to 4 MB.

After that test was done, I decided to use the Dynex Multi-card reader to test the read and write speed of this particular card. The Dynex card reader is SDHC compatible, and has proved that the bottleneck of my built-in SD Card reader skewed one of my results here. I just want to make sure that the card reader was not the bottleneck and thus test the true speed of the SD card itself.

To test, I copied a 700 MB solid file (WinXP Pro SP2 ISO file) to the freshly formated card (FAT32), then read back from it. It took 2:42 minutes to write to the card, which equates to 4.32 MB/sec. This falls way below what a Class 6 card should write at! Of course, the SDHC ADATA card I tested here tested way faster than that, and it was also a Class 6 card.

Read speeds, however, is very impressive. It took 31 seconds to copy the entire file back to the internal hard drive, which equates to 22.58 MB/sec! The trend still seem the same, where read speeds are faster than write speeds. However, in this case, it seems that the gap has widen.

While PQI advertised this card to be a Class 6, it was very unfortunate that it did not live up to the promise. But looking at the numbers, it's adaqate for high MP cameras that write 3 to 4 MB each photo. It's also just fine when recording video at their highest settings (normally MP4 video that are at most 600 kb/sec).

Transfering photos to your PC won't take long at all, thanks to the super fast read speeds. You do need a card reader that supports these new SDHC cards, however.

Conclusion
It was an unfortunate surprise to see the PQI's write speed fall short of expectations. However, it is decent enough to perform well for high MP cameras (especially most point-and-shoots). For professionals who have cameras that are VERY speedy, taking high MP photos at almost video-like speeds (5-15 frames per seconds) may actually overwhelm the SD card with data needing to be written. This is what Extreme III cards (and cards like them) are made for.

For MP3 players or other devices that only stream data from SD cards, this is more than just fine for that purpose. My Treo 650 was able to use this card to launch Palm applications and stream MP3, videos, and photos without a problem. My Garmin nuvi 760 also seem to display photos and play MP3s just fine off the card as well.

So what of the PQI 8 GB Class 6 SDHC Card? Despite the slow write speed, should it be considered? Well, the price was right for me, and capacity was the main reason I bought the card, not the speed. Though disapointed that it didn't deliver the write speed as promised, the capacity at the low price of $14 was well worth the trade off.