Mark J  wrote:
> In message 
>           bob oing  wrote:
>
>> Some months ago I bought a Samsung Evo + microSD card as a boot
>> device for an RPI3B (under FreeBSD-current). Initially it seemed
>> as fast or faster than Sandisk Extreme cards used previously.
>
>> Lately, it's become extremely slow. At first I thought it might be
>> FreeBSD's fault, but now I'm starting to wonder if the card is the
>> culprit.
>
>> Has anybody observed similar behavior under Raspbian?
>
>> Thanks for reading,
>
>> bob prohaska
>
> Maybe OTT, but...
>
> I bought four 64GB Samsung Evo+ on eBay (stupid, I know) and they were ALL
> fakes, but their packaging was convincingly genuine. They were extremely
> slow putting an OS on, and had announced themselves as 67GB. Using fsprobe
> (Linux, but based upon Windows h2testw) they were all below 16GB - their
> controllers had been tampered with. Doing a Benchmark using an SDcard
> reader via UbuntuMATE gave most revealing graphs which were far from
> normal. The seller was confident that I was bluffing, and refused to give
> a refund unless the cards were returned. A challenge via eBay did nothing,
> but one via PayPal went uncontested, so I got my money back. An
> unfavourable review on eBay, repeated several times, never got published.
> Caveat emptor...
>
>

No reason so far to suspect a counterfeit.

Initial performance on my card (128 GB) was quite good. Things didn't
get slow for several months. At that time I accidentally allowed the
card to reach some 97% of capacity, which I'm told is bad for them.
However it didn't stop working and I cleaned house, getting it back
to about 77 % of capacity. At roughly the same time I noticed a slowdown
when storage activity was high, for example when extracting tar files.
The sluggish performance has persisted for over a month, but the card
hasn't failed in any decisive way.


Since this is on FreeBSD-current, with which people are constantly
tinkering, I first suspected an OS problem. No supporting evidence
for that proposition has emerged, so I'm casting a wider net.

Thanks for reading,

bob prohaska

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