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[sheddyian]

I've been using a Raspberry Pi as a media centre, running Raspbmc for some time now, and the other day thought I'd rebuild it as it's been through multiple crashes.  I also wanted to install onto a USB stick rather than the SD card, as this is said to be faster.

Anyway, after I'd noted appropriate data from the original SD card, and reformatted it, I ran HD Tune over it to test it's (read) performance.  (1st pic)

Oh - that doesn't look very good.

A solid state device ought to give a flat read time (top line), not jumping about like that.  I retried it, and got similar results.

I tried reformatting it, even repartitioning it, and still got similar results - not a very flat line at all.

I downloaded and ran the SD Card association card formatting tool, set to quick format, and even that had no difference.

But on a whim, I tried setting the SD Card tool to do an erase format, and after waiting 15 minutes or so for it to complete, I retested the card with HDTune.  See the 2nd pic for results!

Now, the Raspberry Pi had crashed a number of times, and the card has had quite heavy use, so whilst I might not be all that surprised at the state of the card before formatting, I was surprised at the problem remaining aftweards, until I did an erase as well.

Thought I'd share this in case anyone else is curious or has been having strange performance issues with SD cards, especially well used ones.

Ian

Links :

HD Tune http://www.hdtune.com/
(Windows Only, I think.  The paid version has lots of features, but I'm using the free one)

SD Format tool https://www.sdcard.org/downloads/formatter_4/
(Windows & Mac)

[kitz]

Thanks for sharing the info 

[sheddyian]

I've just found another one!

I was rummaging for a USB drive to use, and I found an old 8gb one that I got from Aldi some time ago, so probably not top quality. 

I ran HD Tune over it, and got the results as shown is the first attachment.  Pretty rough. 

Just to confirm that it's not something odd with this computer, I tried it on a 2nd PC, and got very similar results.  The graph jumps up and down wildly.

I performed a quick format on it, and nothing much changed.

I then ran the SD Format over it, set it to do an Overwrite erase format.

I removed the USB stick (as instructed by the formatter), reinserted, and retested with HD Tune.  The significantly better results are in the 2nd attachment.

I've often found that old Hard Disk drives can be reinvigorated by a "low level" format (I boot from a CD containing MHDD and erase with that), but I hadn't realised an erase would also envigorate solid state devices too.  How odd.

Code: [Select]


item            min     max     ave    access    burst
As found :
8gb on PC1      4.6     12.1    10.3     0.9       2.8
8gb on PC2      4.5     11.9    10.0     0.9       3.2
After SD Format:
8gb on PC1     14.3     15.9    15.3     0.8      13.8
8gb on PC2     15.0     16.1    15.7     0.8      13.7

Very curious!

I would be interested to hear from anyone else who cares to try using HD Tune on an old SD card or USB stick.  Do you see the same as I've been seeing?

Ian