[G1 Accessories] ofsinreno:
I manage a consumer electronics store and a lot of people seem to be misinformed when shopping for memory cards for new mobile devices. After spending a year or so on this site it seems many people here are misinformed as well- so I thought I would open up a discussion.

When looking at memory cards (micro in this case; but most follow the same format) there are 3 important pieces of information to review.

1. Capacity- some people will do fine with a 1gig card while others use their device to store music, movies, and pictures and need more space. At the time of this post the largest micro-SD card available (as far as I know) is 16gig.

2. Speed rating- obviously you want the most performance you can get out of a memory card so any information stored on that card can be accessed quickly, and with so many new ROM's running apps from the SD card the transfer needs to be both fast and efficient. Most cards offer anywhere from 6mb/sec to 15mb/sec (with other types of flash speeds near the 45mb/sec range). The speed rating is a rating of the MAXIMUM READ/WRITE SPEED capabilities, and is often difficult to find on the product info- even more difficult to measure.

3. Class rating- is the most misunderstood rating of all- and the most advertised (the class rating is written on the front of most cards). The class rating IS NOT a measure of how fast information can be accessed from the card by the device. Most people believe that a class 2 card is guaranteed to read/write at 2mb/sec while a class 6 is guaranteed to read/write no slower than 6mb/sec, the next logical step is to believe that a class 6 card will be faster and more efficient than a lower class. THIS IS NOT TRUE. What the class rating is actually defining is whether or not the card will work in your device. A class 6 card will only function properly in a device that can SUSTAIN a write/read speed of 6mb/sec. Where a class 2 card (with the same speed rating) will work in any device that can write at least 2mb/sec or more; and will do so AT THE SAME SPEED AS THE CLASS 6.

Many people believe that the discrepency lies in the branding of the card, for example some say that no-name brands will produce a substandard card and call it a "class 6", which will result in lower transfer speeds. Again, this is not true. The class rating HAS NOTHING TO DO WITH HOW FAST THIS CARD WILL PERFORM. If your device reads/writes at 15mb/sec it will perform the same with a class 2 as it will with a class 6. The only time class ratings matter is if you have a device (usually a digital camera) that writes slower than 6mb/sec- which the G1 does not.

I don't understand why ROM developers (and no disrespect intended, I have an unbelieveable respect for devs) make a notation that HERO ROM's need a class 6 memory card to function. We sell 16gig Sandisk microSD cards with a class 4 rating, and I constantly get customers who tell me they are going to wait for Sandisk's class 6 16gig microSD card. As of today Sandisk has no intention of making a class 6 16gig microSD card. And if they did, it would not be any faster than the class 4 that is currently available.

This is the information I have gathered by speaking to the Sandisk and Delkin engineering departments as well as countless searches, and I hope it saves someone some $$- which is my intent.