Hi John ...
Thanks for posting this info.
Shel
[Original Message]
From: John Celio
> Are all SD cards more or less equal, given storage volume?
Oh god no! Not even close.
There are some very important things to know about memory cards before
you
go and buy one, but unfortunately these things can be hard to find out
from
the memory manufacturers.
One of the things I do at my job is image recovery for customers whose
memory cards have become unreadable for whatever reason. I get
about six
or
seven image recovery requests per week, and I've noticed some trends:
-- The majority of memory cards that come to me with problems are those
cheapass SanDisk cards that are sold just about everywhere
(especially at
places like Costco and Wal*Mart). Note: this group does not include
Ultra
or Extreme cards.
-- The next largest group of cards to come to me are "no name" memory
cards. "No name" refers to cards from a brand no one (in my lab,
anyway)
has heard of or cards with no brand at all. Many of these cards come
from
online retailers who package them with a camera to sweeten the deal, or
from
the customer having to purchase more memory from a tourist trap while
travelling.
-- The smallest group consists of "professional" cards. In the last
couple
weeks, I've seen two SanDisk Ultra IIs, one SanDisk Extreme, and one
Lexar
Professional (which is the brand I use, and which I actually rarely see
come
to me with problems).
What separates these groups?
Memory manufacturers generally have three tiers of quality, and they
affect
the speed and reliability of the memory in each tier.
Tier 3: This is the cheap stuff. Cheapass SanDisk cards fall in this
category, as well as most other cheapass memory you find (this includes
cheapass memory you can buy for your computer and whatnot). If you were
to
open a tier 3 memory card, you would see more than one piece of flash
memory. If, for example, you bought a 512mb card and opened it up, you
would most likely see four pieces of 128mb flash memory inside. These
modules are cheaper to produce, and so the manufacturers produce them en
masse and combine them into larger capacity cards. More memory modules
means higher chances of getting defective memory, as well as slower
transfer
rates, but lower prices. Consumers buy this stuff because they think
they're getting a good deal, but in fact they're playing roulette with
their
data.
Tier 2: This stuff is usually produced from a couple memory modules, but
not
as many as Tier 3 cards. The modules have higher capacities (in some
cases
there is only one piece of memory in tier 2 cards) and are usually
produced
under tighter quality controls. These cards are faster than tier 3
cards,
but not always as fast as Tier 1 (though they can be very fast).
Tier 1: This is the high-end stuff. You generally get what you pay for
with
tier 1 cards. They are made from a single memory module, and are
generally
very fast (depending on the technology available at the time they were
designed, of course). They are produced under the tightest quality
controls, and are often tested at the factory before being shipped.
Lexar
Professional, SanDisk Extreme, and SanDisk Ultra cards fall under this
category, but in my experience with so many bad cards, the Lexar
Professional cards seem to be the most reliable (though admittedly not
always as fast as the SanDisk cards)
So, after learning all this, it has become my opinion that, when buying
memory, one should spend the extra money and get professional-quality
stuff.
You really do get what you pay for.
John Celio
