What a difference Over Provisioning makes

Intel 520 240GB

What a difference Over Provisioning makes

Controller Type: LSI Sandforce 2281

NAND type: IMFT 25nm MLC

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What you see here is a scatter chart of the IOPS performance
level recorded every second of the two hour test run. The red plots are for
the run with the SSD’s standard OP area and the blue plots are for the run with
an additional OP that takes the total OP to 96GB.

Clearly, it is obvious that the additional OP is making a
significant and positive difference to performance.

You can also see that the deviation of the plots around what
can be considered to be the norm is wide and unpredictable.

Notice also that the plots start relatively high and then
drop significantly to a Steady (though unpredictable) State.

We believe the first drop in both plots occurs when all of
the NAND has been written to once and the drive’s Garbage Collection
functionality kicks in to erase blocks in preparation for accommodating future
writes.

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You will also notice that the plots for ‘with extra OP’ take
a second significant drop (at around 1500 seconds) before they reach a Steady
(though unpredictable) State. Our theory is that this second step is where the
drive’s Sandforce controller starts to throttle the write performance as part
of its ongoing duty to preserve NAND life expectancy.

Please click here
for our review of the Intel 520 240GB.

Let’s go to the next page to look at the results for a
Corsair Neutron 240GB

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