John Galea's Blog

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USB Flash cards and microSD Flash cards

I looked into buying a new USB flash drive. My biggest one is only 1G so I thought it was time. I was totally shocked at how the companies mislead customers and do nothing to help them understand their products. misinformation …

I bought a Patriot XPorter which touts 200X performance. (product specs) from Canada Computers for $20 for an 8G. Right off the bat I’m looking and thinking to myself WTF does 200X mean? Well it turns out they are referring to the old 1X CDROM spec. So what this means is the old audio standard 44.1K x 16 bit’s per sample x stero yielding roughly 150K/s x 200 or 30MB/s. But if you read the fine print this is on read not write. Now we read more often than we write so that is a good place to have performance. So here is what I was able to get in performance:

As you can see on read (verify on the screen) I did get 26.9MB/s so pretty close to the 30MB/s they advertise (once you sort out what they were saying).

There is a higher performance version from Patriot that would up the write speed to 25M/s from 10MB/s for a small price premium but again they did not explain it well enough for me to decide to buy that one. And they even label the speed differently. Patriot Rage

So one of the uses I had for this drive was to use it in place of a CD/DVD for loading up new machines. So you need to find a way of making it a bootable USB flash drive and take an ISO of an operating system and put it on the flash drive. Turns out there are lots of tools out there to do so and lots of guides too. All free! CDs are terrible at any form of random access due to the large circumference of the CD/DVD and the relatively slow rotating speed of removable media.

MicroSD cards (and SD cards) are labelled a little different again. They are rated on their “Class”. They have a logo with a C and a number on the card. That number tells you the write speed of the card. So for a Class 4 card you get a write speed of 4MB/s. Which unfortunately does not tell you the read speed. Recently the flash manufactures have kicked everything up a notch and come out with Class 10 cards. I recently bought an A-data 32G Class 10 microSD card. According to the store I bought it from, Canada Computers , for $79 (product specs) they have been in their store for about 3 weeks. I see Kingston are also showing a Class 10 card but at higher prices (due to their name of course). This Adata seem to be more readily available.

If you buy cards on ebay and the like be sure and be careful. First there are knock offs out there that are not really the capacity on the card and second often they do not mention the speed of the cards.

Be aware that not all devices are designed to take advantage of faster cards. So buying faster cards may or may not be of any use. And trying to figure out if it will help is almost impossible. This includes card readers by the way. Not all are made alike.

So I ran a test of the 32G microSD class 10 card from Adata and was astonished to see it actually exceeded class 10 and was 100% the size it should be.

I ran a second test on the same card using a no name reader and the speed went down to 9.25/11.6 Vs 13/14.1 a decrease of 30%!

By the way, when you stick a USB Flash card in you get one device out of it which is a USB mass storage device. When you stick a card into a reader you actually get two, the reader and the card. This is why some devices like car stereos will support a USB Flash card but not a card in a reader.

You should also be aware that not all devices support 32G. Some stop at 16G. A fact I don’t really understand. There was a break at 4G, 4G and above are considered SDHC (high capacity) which some devices support and some do not. My camera for example does not.

On my HTC Desire Z I was able to get a speed shared through the phone of 9.59 meaning it is exercising the faster speed of the card and it does indeed support 32G!


June 14, 2011 - Posted by | Other reviews, Uncategorized

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