The Dual Slot Adapter fits snugly inside the Memory Stick Duo adapter.
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.2.4 SanDisk 128GB PSP.3.5 (Dual Slot Adapter) Samsung EVO slot machine game on app store 64GB USB.
If prices are similar, you might want to try the Samsung due to the boasted durability features and its higher Class 10 speed.
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.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.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.Samsung EVO Differences, so, what does the Samsung EVO micro SD card offer?No matter how fast the micro SD cards might be, they are restricted to the hardware in which they are used.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.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.Your usable capacity will differ.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.

The ext3 and ext4 file systems actually format to a lower usable capacity because those file systems automatically reserve 5 storage.
The same USB.0 card reader was used in both tests.
Performance How fast is fast?
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.The same is true with the Samsung EVO.Upgrading to Samsung EVO cards did not make the PSP any faster except when transferring files with a computer.However, the adapter resides inside a device, which protects the micro SD cards from the outside elements.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.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.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.Even though benchmarks reveal faster numbers for the Samsung EVO, I could not see any noticeable difference during PSP usage.According to the back of the packaging (because that is what is in front of me the Samsung EVO micro SD claims.