Transcend Multi-Card Reader RDF9 Review

Introduction

The Transcend USB 3.1/3.0 UHS-II Multi-Card Reader RDF9 is an update to the RDF8. The RDF9 adds support for UHS-II SD cards in the full-size SD slot and also accepts UHS-I SDHC, SDXC and standard SD cards. Additional slots are provided for microSD/microSDHC/microSDXC, CompactFlash (including UDMA7 support) and Sony Memory Stick cards. The reader offers an increase in performance, which is advertised up to 260 MB/s read and 190 MB/s write speeds, a result of UHS-II SD card support. The full product number for the product in this review is TS-RDF9K.

The RDF9 has a gloss black top and matte black sides and bottom. When the reader is plugged in to USB power a bright LED shines through the top of the case. This light blinks when a card is accessed. Dimensionally, the RDF9 measures the same as the RDF8 at 2 5/8 x 1 3/4 x 5/8 inches (67.6 x 45 x 15.2 mm). The reader is extremely light and weighs only 32 grams (without cable). The bottom of the reader is made of the same hard plastic as the rest of the case; there is no pad to hold the reader in place. The sticker on the bottom of the reader notes the reader was made Taiwan in 2015.

The CompactFlash card slot is nearly 7/8 inch deep. It does have some side-to-side play. This is similar to the previous model but it has not been an issue provided some care is used when inserting cards. CF cards insert easily and seat snugly on the pins. The SD card slot is nearly one inch deep to accommodate the additional row of pins used by the UHS-II interface. Compared with most other UHS-II readers, SD cards slide in very easily with almost no resistance. The microSD slot has some resistance, but it is not appreciably different from other microSD readers. Although microSD cards insert far into the reader and only about 2mm remain outside, the design of microSD cards provides just enough lip to aid in removal.

The RDF9 is listed as USB 3.1 and 3.0, but it is USB 3.1 Gen 1 only. These standards are technically equivalent and use the same cable, connectors and support up to 5Gbps transfer rate. The reader does not support the faster USB 3.1 Gen 2 that would provide up to 10Gbps. This is a moot point because the reader can not exceed USB 3.0 speed. A 15-inch USB A to Micro-B cable is included. The cable is similar in appearance to the one included with the RDF8 reader, but unlike the cable included with the previous reader, this one fit much more securely in the Micro-B port on the back of the reader.

The Transcend RDF9 is compatible with Mac OS X 10.5+ as well as Windows XP, Vista, Win 7, Win 8 and Win 10 with the latest service packs. The RDF9 reader has a 2 year warranty.

Performance

Transcend advertises the RDF9 at 260 MB/s read and 190 MB/s write speeds. Using the Toshiba Exceria Pro UHS-II 32GB card the RDF9 reached a maximum 254.4 MB/s sequential read speed. This is close to the 260MB/s rating of the reader. Sequential write speed exceeded the rating and measured 232.3MB/s using the Lexar 2000x UHS-II 32GB card.

It should be noted that the microSD slot only supports UHS-I. Although UHS-II microSD cards can be used in the slot they will function in UHS-I mode and be limited to 104MB/s or below. In the results below, UHS-II microSD cards were tested in the full-size SD slot using a UHS-II microSD to SD card adapter. Such an adapter is included with Lexar 1800x UHS-II microSD cards.

CompactFlash card write speed is improved over the previous RDF8 model. The RDF9 reached up to 155 MB/s sequential write using Lexar Professional 1066x CF cards, whereas the old reader topped out at 139 MB/s using the same cards. Read speeds were slightly higher, with the highest benchmark at 160.5 MB/s sequential read using a Lexar Professional 1066x 32GB CF card. The old reader reached a high of 157.4 MB/s sequential read.

It is possible to read and write multiple cards at the same time in the RDF9, but this will slow the overall transfer rate. With three concurrent read operations, one card would often lose almost all speed, while the other cards would alternate the remaining priority. In the best case, one read and two write transfers were split evenly at about 40MB/s per card. In reading two cards, the total speed was lower than reading one single card. In all instances single transfers resulted in higher speed than the sum of concurrent transfers.

Reader: Transcend Multi-Card Reader RDF9
Benchmark: CrystalDiskMark 3.0.3 x64
Program settings: 1000 MB, 5 passes, random test data
Operating system: Windows 10 Pro
Motherboard: Gigabyte GA-Z77X-UD3H
Processor: Intel Core i7-3770K @ 4.40GHz
RAM: 32GB DDR3 1600

Conclusion

As a compact, lightweight card reader the RDF9 has a lot to offer. Its main improvement over the RDF8 is UHS-II support for fast SD card transfers. CompactFlash card write performance also improved but that may not be an important consideration for photographers. Read performance with UDMA7 CF cards and UHS-I cards was generally similar between the RDF8 and RDF9 readers.

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The Transcend RDF9 reader (TS-RDF9K) is a new release and not yet widely available. It is currently available for purchase worldwide from the following retailer:

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