Samsung 840 EVO mSATA 1TB SSD Review

Not that long ago, Samsung acquired a software company
‘NVELO’ who specialise in SSD caching software. At the time, I and many others
were rather puzzled why Samsung made this acquisition. Well, now it becomes
clear.

Samsung’s Magician software (4.3) supports ‘Rapid’ mode on
selected Samsung SSDs, currently the 840 EVO SATA and mSATA models, and also
the 840 Pro. Only one SSD in the system can run in ‘Rapid’ mode, regardless of
how many qualified SSDs are installed.

Basically what ‘Rapid’ does is use system RAM as a cache, where
regularly used applications and data are stored in Rapid’s cache. Since system
RAM is very much faster than NAND, a huge boost in performance can be gained.
This is especially true for small random files at low queue depths.

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Rapid mode uses a filter driver which monitors the file
systems I/O activity, and will intelligently cache the data that the user
accesses most frequently. Up to 25% or a maximum of 1GB of system RAM will be
used for "Rapid’s" cache.

I decided to run some tests, comparing ‘Rapid’ mode with
normal mode, and will present the results below by simply showing screenshots
of the two modes. In each test I will first show the result of ‘Rapid’ mode,
then follow that with the result obtained in normal mode.

AS SSD

Samsung 840 EVO mSATA 1TB SSD Review
Samsung 840 EVO mSATA 1000GB – Rapid mode

Samsung 840 EVO mSATA 1TB SSD Review
Samsung 840 EVO mSATA 1000GB – Normal mode

As we can see, writing speeds especially have risen by a
huge margin, and sequential reading speeds have also received a large boost.

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Samsung 840 EVO mSATA 1TB SSD Review
Samsung 840 EVO mSATA 1000GB – Rapid mode

Samsung 840 EVO mSATA 1TB SSD Review
Samsung 840 EVO mSATA 1000GB – Normal mode

Once again, we can see a massive boost in writing performance,
with an incredible 697K IOPS witnessed for 4K random writes at a queue depth of
16. Reading speeds are also up, but by a more modest margin.

IOMeter 4K random write (QD1)

Samsung 840 EVO mSATA 1TB SSD Review
Samsung 840 EVO mSATA 1000GB – Rapid mode

Samsung 840 EVO mSATA 1TB SSD Review
Samsung 840 EVO mSATA 1000GB – Normal mode

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Once again we can see a massive boost in performance, with
4K random writes up from 147.51 MB/s to 523.64 MB/s.

IOMeter 4K random read (QD1)

Samsung 840 EVO mSATA 1TB SSD Review
Samsung 840 EVO mSATA 1000GB – Rapid mode

Samsung 840 EVO mSATA 1TB SSD Review
Samsung 840 EVO mSATA 1000GB – Normal mode

This time there is only a small increase in performance.

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IOMeter sequential write (QD1)

Samsung 840 EVO mSATA 1TB SSD Review
Samsung 840 EVO mSATA 1000GB – Rapid mode

Samsung 840 EVO mSATA 1TB SSD Review
Samsung 840 EVO mSATA 1000GB – Normal mode

Low queue depth sequential writes receive a large boost in
performance, up from 509.86 MB/s to 709.29 MB/s.

IOMeter sequential read (QD1)

Samsung 840 EVO mSATA 1TB SSD Review
Samsung 840 EVO mSATA 1000GB – Rapid mode

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Samsung 840 EVO mSATA 1TB SSD Review
Samsung 840 EVO mSATA 1000GB – Normal mode

This time we see a slight decrease in performance.

PC Mark 8

To see what would happen with a real world scenario, I also
ran PC Mark 8 HDD suite in Rapid mode.

Samsung 840 EVO mSATA 1TB SSD Review
Samsung 840 EVO mSATA 1000GB – Rapid mode

Samsung 840 EVO mSATA 1TB SSD Review
Samsung 840 EVO mSATA 1000GB – Normal mode

The ‘storage bandwidth’ score has risen substantially in
‘Rapid mode’.

Summary

As we have seen from these tests, there is a large boost in
performance to be had from running in ‘Rapid mode’, at least with synthetic
benchmarks. So how will this translate into the real world?

Time did not allow for an extensive study into real world
performance with ‘Rapid mode’ enabled. For the short time I did have Rapid mode
enabled on the 840 EVO mSATA 1000GB SSD, there was the feeling of the system
being more responsive, but this is difficult to quantify. The PC Mark 8 score
did rise, but not by a huge margin, although bandwidth did increase by quite a
large amount.

One thing that is clear is, as the Rapid mode driver
matures, it gets faster with each new version. The version that is installed
with Magician 4.3 is a good deal faster than the beta version that was
available when I tested the SATA version of the 840 EVO.

So what is the downside of using Rapid mode?

I would say that before you even contemplate using ‘Rapid
mode’, you should ensure that your system is 100% stable. As you’re going to
have your data in a RAM cache for a time before it’s permanently committed to
NAND, a system crash, or for that matter a power outage, could result in data
loss.

Having said that, my system is very stable, and I have been
running in Rapid mode since September 2013 on the 840 EVO 750GB SATA model, and
have not come across a single issue with Rapid mode whatsoever.

 

Now let’s head to the next page, and see how well the
drive performs after heavy use….

 

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