Niall’s virtual diary archives – Monday 15th April 2013

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Monday 15th April 2013: 6.36pm. Link shared:

Finally got my mSATA USB 3.0 enclosure which I had to order from the US. With a Crucial M4 mSATA SSD inserted, my Samsung ARM Chromebook gets:

iozone -e -I -a -s 1000M -r 4k -r 512k -i 0 -i 1 -i 2

                                                            random  random    bkwd   record   stride                                   
              KB  reclen   write rewrite    read    reread    read   write    read  rewrite     read   fwrite frewrite   fread  freread
         1024000       4   10509   11524    11235    11548    9039   11808                                                         
         1024000     512   38881   39764    40345    40290   39491   38930                                                          

In other words, about 10Mb/sec for 4k reads and writes with no real difference if they're random. And a peak transfer rate of ~38Mb/sec, also with no real difference if it's random. All these suggest it's the USB 3.0 controller which is getting in the way. These results were expected of course (see

If there ever was an example of USB 3.0 controller limited performance, it is the above: Samsung's Exynos 5 ARM chipset's USB controller really is not great. That SSD should hit 250Mb/sec reads over USB 3.0 :(

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