Samsung EVO 64 GB Micro SD and the 128 GB Memory Stick Pro Duo Adapter

September 30, 2014
evo1A while back I gave my impressions about using two SanDisk 64 GB microSD cards in a dual-micro SD adapter to produce a single 128 GB Memory Stick Duo for Sony devices.

This 128 GB arrangement continues to work superbly despite the slow transfer rates limited by the dual-micro SD adapter.

Since then, Samsung has introduced the Samsung 64 GB EVO microSDXC card that is supposed to offer faster transfer rates and increased durability.

Does it? Here are my thoughts based upon my usage.


Micro SD cards are great! Suppose you have three different devices, and each device requires its own card type: SD, Micro SD, and Memory Stick Duo. You want to give each device 64 GB, but this means purchasing three different types of memory cards — each with a 64 GB capacity. This can get expensive.

Why not have one 64 GB card that will fit in each device using an adapter? This is where micro SD proves its worth since it is small enough to fit in almost any type of adapter that supports it. Instead of having three different types of memory cards, use one 64 GB micro SD and share it among the three devices using adapters.

This can save a bundle of money and offer increased storage space. Especially for Sony Memory Sticks that might not offer 128 GB and higher capacities. Also, if those capacities are available in the Memory Stick Pro Duo format, then they tend to be more expensive than other formats, such as SD.

Of course, other factors, such as file formats and needed transfer rates, might affect performance, but I have been very happy with the micro SD route.

128 GB Memory Stick

Sony devices often require expensive, proprietary Memory Sticks. I wanted 128 GB of storage space, but a 128 GB Memory Stick did not exist at the time. What to do? One usable trick is to obtain a dual micro SD to Memory Stick Duo adapter, and use two 64 GB micro SD cards for a total of 128 GB. Sony cameras, video recorders, the PlayStation Portable (PSP), and computers see the Memory Stick Pro Duo as a single 128 GB card. It works beautifully, but the access times are slower due to the slow speed of the dual-slot adapter.

Samsung 64 GB EVO Class 10

How does Samsung’s micro SD card compare to the SanDisk micro SD? Does it really offer 48 MB/s transfer rates? First, here is a look at the packaging.


Front of the Samsing 64 EVO packaging. Class 10 cards boasting “up to” 48 MB/s. SD adapters included. Two are shown here because I wanted to create a single 128 GB Memory Stick Pro Duo card for Sony devices.

The front of the package proudly proclaims Class 10 48 MB/s performance.


Here is the back of the package that contains the fine print explaining (in four languages) that 1 GB = 1,000,000,000 bytes (10^9) and not 1,073,741,824 bytes (2^30) even though files sizes are quoted in powers of 2. Contains additional fine print explaining that your usable capacity “may differ” from the 64 GB quoted in big, bold lettering on the front of the package. (Take a look at the front of the package again.) ‘Tis no lie. Your usable capacity will differ.

Micro SD Cards are small. The Samsung EVO includes a micro SD to SD adapter to fit the micro SD card into devices that only accept SD cards.


Micro SD and the included SD adapter. The small, gray tab at the top of the adapter controls read-only access.


The micro SD tucks neatly inside the SD adapter.


The S3 Ultrabook only has an SD port. Using the SD adapter, it can read the micro SD card.

Samsung EVO Differences

So, what does the Samsung EVO micro SD card offer? According to the back of the packaging (because that is what is in front of me), the Samsung EVO micro SD claims to be…

  • Water Proof
  • Magnet Proof
  • Temperature Proof
  • X-Ray Proof
  • Class 10

The Samsung EVO card feels just as light, small, and flimsy as other micro SD cards, so I have no idea how true these claims are. This was a pricey item at the time of purchase, so I have no intention of deliberately placing the wafer-thin card through physical stress tests to find out.

I have been using two of these cards for the past several months, and they continue to perform reliably as a single 128 GB card in a dual adapter. However, the adapter resides inside a device, which protects the micro SD cards from the outside elements.

Capacity and Formatting

A single card arrives preformatted with exFAT and 58.55 GB of free space.


GParted in Linux. Shows one Samsung EVO 64 GB Micro SD card preformatted with exFAT and 58.55 GB free space. This system would not read exFAT, so I reformatted the card to FAT32 for better compatibility with a range of devices.


Linux is supposed to format and read exFAT, but the system I used was not able to read the preformatted micro SD card straight from the package.


GParted formatted the Samsung 64 EVO to FAT32, which makes the micro SD card compatible with almost any device. Linux read the card perfectly. The formatted capacity is still 58.56 GB. I had to use Linux to format the card with FAT32 since Windows 7 only offers the choice between NTFS and exFAT with the simple format option.


Samsung 64 EVO formatted to the ext4 file system. Notice that 1.10 GB is used. This is normal for ext3 and ext4, but it can be changed to provide more free space.


Xubuntu 14.04. The Samsung 64 EVO is seen as a 63 MB device. Here, it is formatted with ext4 with 5% reserved space by default.


sudo tune2fs -m 0 /dev/sdc will remove the reserved space. This makes more free space available. (/dev/sdc is the device file of the micro SD card. This might change according to the system.)

128 GB Memory Stick Duo Using Dual Adapter

Two Samsung 64 GB EVO micro SD cards will fit in a Memory Stick Pro Duo Dual Slot Adapter to create a single Memory Stick Duo card that is ~126 GB in size (before formatting). No, the 126 GB is not a typo.


Exercise care when inserting the micro SD cards into the adapter since the adapter feels cheap and flimsy compared to the micro SD cards themselves.

One micro SD card fits in the slot marked 1, and a second micro SD card fits in the slot marked 2.


The combined card is just as small and thin as a regular Memory Stick Duo, so it should fit in any device that accepts this type of card. The dual adapter is delicate, so handle it carefully!

The device sees the Memory Stick Duo as a single 126 GB card. It is formatted and used like any other card. However, once formatted, the micro SD cards must not be removed from the adapter or else there will be a risk of data loss. File information seems to be stored on the first card, so data residing on Card 1 might still be accessible, but if Card 2 is removed, then data stored on it cannot be retrieved. As a simple rule, treat the two micro SD cards as one card after formatting, and avoid removing them from the adapter.

The Dual Slot Adapter can be inserted in a Memory Stick adapter for devices requiring a Memory Stick.


A Memory Stick Duo adapter and the Dual Slot Adapter.


The Dual Slot Adapter fits snugly inside the Memory Stick Duo adapter. Any device requiring the older Memory Stick should access the Dual Slot Adapter within.

Less Samsung EVO Capacity

As a quick example (and because screenshots are easier to take), let us look at the capacity of the 128 GB Memory Stick Duo in a PSP. The Dual Slot Adapter with two Samsung 64 GB EVO cards formats normally to FAT32 just like the dual 64 GB SanDisk arrangement.


PSP asking to format the 126 GB dual-slot Memory Stick Duo.


Card formatted successfully.

So far, so good. Let’s see how much space is available after formatting.


117 GB of free space available? What is going on?

The 128 GB Memory Stick using two Samsung EVO 64 GB micro SD cards formats to 117 GB. We would think that 64 + 64 = 128, but with two Samsung 64 EVO cards, it is 126 GB. This is 9 GB less than a 128 GB adapter containing two 64 GB SanDisk micro SD cards that formats to 126 GB (126 – 117 = 9). Is something wrong?

Samsung EVO 64 GB x2 (128 GB): 117 GB Formatted
    SanDisk 64 GB x2 (128 GB): 126 GB Formatted (Usually 127.7 GB)

After much formatting and reformatting, I believe this is normal because the Samsung 64 EVO cards offer less space than the SanDisk micro SD cards. Two 64 GB Samsung micro SD cards always format to 117 GB no matter the device or file system. FAT32, ext3, ext4, and NTFS all format to ~117 GB when the adapter is used. I formatted this device multiple times using Linux Mint, Xubuntu, and Windows, and the resulting formatted capacity was always approximately 117 GB.

The ext3 and ext4 file systems actually format to a lower usable capacity because those file systems automatically reserve 5% storage. This can be reduced to 0% using tune2fs, which I did, but even after tune2fs set the reserved storage to 0%, the resulting usable capacity was still 117 GB.

117 GB is still plenty of space for such a tiny card combination, but be aware that the formatted capacity of two formatted 64 GB Samsung EVO cards will be lower than two formatted 64 GB SanDisk cards. To be fair, the SanDisk micro SD cards were obtained quite some time ago, so perhaps today’s SanDisk cards offer less formatted storage space?

PSP Performance

As another quick example, let us use the PSP again since it is a familiar device. Performance of the dual Samsung EVO is the same as the dual SanDisk. There is still a short wait when the PSP enters the XMB as it reads the Memory Stick just like it did with the SanDisk cards.

PSP Card Access Speed

However, music, videos, pictures and game save data all access with the same fast and snappy response as before. Data reads and writes from and to the PSP via its USB 2.0 interface at the same transfer rate as before. Upgrading to Samsung EVO cards did not make the PSP any faster except when transferring files with a computer. This is most likely due to the limitations of USB 2.0 and the PSP itself. No matter how fast the micro SD cards might be, they are restricted to the hardware in which they are used.


How fast is fast? I ran two benchmarking programs using Linux Mint 17 and Windows 7 in order to get an idea of the Samsung EVO’s performance in different operating systems.

For Linux, I used the built-in benchmark from the Disks utility (Linux Mint Menu > Accessories > Disks), and for Windows 7, I used the CrystalDiskMark program. Numbers were never exact across tests and operating systems. In fact, CrystalDiskMark and Disks rarely agreed. This could be due to different benchmarking algorithms.

We will compare the Class 10 Samsung EVO 64 GB with the Class 6 SanDisk 64 GB card to see if there are any differences between them.

Quick Summary

To avoid suspense, here is a summary of the speeds tested with the Disks benchmark in Linux Mint 17:

Micro SD                 Read MB/s    Write MB/s
SanDisk 64GB USB 3       25.2         4.4
SanDisk 128GB PSP         7.3         4.5  (Dual Slot Adapter)

Samsung EVO 64GB USB 3   34.9        10.4
Samsung EVO 126GB PSP     9.8         6.8  (Dual Slot Adapter)

Keep in mind that we are comparing a Class 10 card with a Class 6 card, so the SanDisk will be slower.

SanDisk 64 GB Micro SD (USB 3 Card Reader with Linux Mint 17)


Disks Benchmark in Linux Mint 17. One SanDisk 64 GB micro SD. USB 3.0 card reader.

A single SanDisk 64 GB card is connected to a Linux Mint 17 computer via a USB 3.0 micro SD card reader so the card reader is not the limiting factor.

 Read: 25.2 MB/s
Write: 4.4 MB/s

CrystalDiskMark in Windows 7 recorded better numbers.


These numbers are much higher than those tested in Linux Mint. The same USB 3.0 card reader was used in both tests.

SanDisk 128 GB Dual Slot Adapter in PSP (2x 64 GB Micro SD)


128 GB Memory Stick Pro Duo (Dual Slot Adapter with two 64 GB SanDisk) in PSP connected to Linux Mint 17 via USB 2 interface.

Read: 7.3 MB/s
Write: 4.5 MB/s

These are low numbers. While the write speed (4.5 MB/s) is about normal, the read speed is a slow 7.3 MB/s. Two factors limit the speeds: 1) The PSP is limited to USB 2, and 2) the Dual Slot Adapter further throttles the speed to about 7-9 MB/s.

Accessing the micro SD cards directly would offer faster read speeds than accessing them through the Dual Slot Adapter.

Samsumg EVO 64 GB Micro SD (USB 3 Card Reader with Linux Mint 17)


One Samsung 64 EVO connected to Linux Mint 17 via a USB 3.0 card reader.

 Read: 34.9 MB/s
Write: 10.4 MB/s

CrystalDiskMark in Windows 7


Topping out at 43.5 MB/s for sequential reads.

No matter if using Linux or Windows, I could never achieve the 48 MB/s rate quoted on the package.

Samsung EVO 126 GB Dual Slot Adapter in PSP (2x 64 GB Micro SD)


Two Samsung 64 EVO micro SD cards in a single Dual Slot Adapter inside the PSP.

“Disk or Device” shows 126 GB total capacity, but formatted capacity is about 117 GB.

 Reads: 9.8 MB/s
Writes: 6.8 MB/s

The Samsung EVO is clearly faster than the SanDisk, even in the PSP. Writes are 6.8 MB/s compared to 4.3 MB/s, and reads are almost 10 MB/s.

CrystalDiskMark in Windows 7 reported similar, lower numbers:


CrystalDiskMark in Windows 7. About 8 MB/s for reads and writes using the 128 GB adapter in the PSP.

“Will I see a difference when using the PSP?”

No. Even though benchmarks reveal faster numbers for the Samsung EVO, I could not see any noticeable difference during PSP usage. Music accessed no faster, pictures viewed at the same pace, and videos played as smoothly as they did before.

However, one advantage is that writing data to the card via the PSP’s USB interface is slightly faster than with the SanDisk arrangement due to the Samsung EVO’s faster write speeds.

Linux or Windows?

The benchmarks above usually show  higher numbers in Windows 7 than in Linux Mint 17. Does this mean that the cards read and write faster in Windows 7?

I would say no because in real-world usage, it takes the same amount of time to transfer a set of files to and from a micro SD card in both Linux and Windows. For example, if it takes five minutes to write files to the micro SD card in Linux, then it will also take five minutes to transfer the same files using Windows 7.

“Should I Upgrade to the Samsung EVO Micro SD?”

This depends. If you already have a 64 GB SanDisk that you use in a slow device, such as the PSP, then the answer is no because you are limited by the speed of the device itself, not the card. Class 10 or Class 6 — it makes little difference with the PSP or slower cameras. You might have a card that can transfer 4,000,000,000,000 GB/s (as an example), but if the device cannot read or write faster than 8 MB/s, then that super-duper card is limited to 8 MB/s.

The same is true with the Samsung EVO. Even though reads and writes are faster than the SanDisk, if used with a slow device or with slow adapters, it will not perform any faster. Take the Dual Slot Adapter, for example. Both the SanDisk and Samsung EVO are capable of faster transfer rates, but when the micro SD cards are inserted into the adapter, they will be limited to ~8 MB/s because the adapter is a slow interface.

However, if you use micro SD cards by themselves without any adapters and with faster devices, then yes, an upgrade will show a slight performance increase.

For those who do not have a 64 GB micro SD card or wish to create a 128 GB card using a Dual Slot Adapter, let price be your guide. You cannot go wrong with either the SanDisk or the Samsung EVO. If prices are similar, you might want to try the Samsung due to the boasted durability features and its higher Class 10 speed. This way, if you obtain a fast camera that benefits from Class 10 speeds, then you will be ready.


The Samsung EVO 64 GB micro SD is a solid-performing card, and I am pleased. It is certainly faster than the Class 6 SanDisk reviewed earlier, but not fast enough to make your eyes pop out and say, “Wow! This is GREAT!” The speed increase is more likely to cause you to merely blink and say, “Oh, that’s nice.” The increase speed is present, but I do not tend to see much difference since I use older, slower cameras.

During the months of usage with the Samsung 64 EVO, I have never experienced data loss of any kind, and the cards continue to perform well.

The only drawback is the available formatted capacity when used with a Memory Stick Pro Duo Dual Slot Adapter to create a 128 GB Memory Stick Duo. The available storage space formats to 117 GB instead of the 128 GB that is possible with the SanDisk cards.

Time will tell how durable the Samsung EVO cards are, but micro SD cards are usually treated tenderly to begin with, so the added “Proof” features might not be a necessity. If you are in need of a new micro SD card, then the Samsung EVO series is worth a look. Other capacities are also available. And, yes, they are compatible with Linux.


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