Transcend RDF8 USB 3.0 Card Reader

With ever increasing pixel counts and larger image files than ever, digital photographers easily can fill up even comparatively large 32Gb cards relatively quickly, especially when shooting in RAW.

Many people, myself included, can get quite anxious to see the results – so downloading images to the computer is definitely a bit of a chore. In the day of USB2.0 card readers, I spent significant time ensuring I got a reader which had decent speed – it is surprising to note that different readers may manage anywhere from 0.6 to 20MB/s transfer rates with many of the cheaper ones settling somewhere near the 6-8MB/s. If you weren’t careful, a 32Gb card could take longer than an hour to download. I don’t have that kind of patience. Also, one had to be careful as some card readers were more compatible with cards than others – and so some brands of readers with nasty chipsets could even corrupt certain kinds of cards. One hasn’t really any likelihood of trying before buying – so it was always going to be a try it and see affair.

Of course, there were a few sites dedicated to the issue of reader and card speed. There has been a lot of combinations tested – but the problem was that these readers are often difficult to purchase and command significant premiums. What I was looking for was a cheaper, easier to buy reader.

What I found was the Transcend RDF8 USB3.0 Card Reader. It can be had for $29 from eBay, which is relatively inexpensive, and mirrors my previous choice of a Transcend USB2.0 Card Reader which was definitely one of the better performing readers I have ever owned.

IMG_5019Transcend RDF8 Underside

The reader is a small unit, just like most modern readers, without much to distinguish it from anything else. It has support for CF, MMC/SDHC/XC, microSD, MS, MS PRO, MS M2. There is a rear microUSB3.0 connector and included short cable.

The internals are easily accessed by popping open the glossy Transcend cover to reveal …

Transcend RDF8 PCB Top

Transcend RDF8 PCB Bottom

… a Genesys Logic GL3220 controller. They are a fairly respected company, probably more famous for their USB Hub and bridge chipsets. There appears to be an SPI flash as well, so it could be firmware upgradable for better support or performance, but at this price, I wouldn’t hold my breath for it. The datasheet itself extols the fact that this supports many of the larger “next-generation” flash card formats, claiming support up to 2Tb (!!!) and also UHS-I cards meaning that this is likely going to be a fast reader. The datasheet also claims CF v6.0 support with PIO mode 6 and UDMA 7 mode support and 48-bit LBA support. All in all, these are the features one should look for on their card readers, but they’re also the features which nobody seems to state clearly on advertisements or packaging!

It definitely fits my bill (on paper at least). Now, it’s time to test it with my family of cards …

Lexar Platinum II 16Gb 200x A-Data Speedy 8Gb CF Samsung 32Gb SDHC Class10 Patriot LX 32Gb SDHC Class10 Team 32Gb SDHC Class10 Kingston 2Gb SDSC

One thing you would notice, is the lack of truly high speed cards. Unfortunately, I haven’t been able to shell out for the top of the range UHS-1 or UDMA7 cards, and if you don’t have the faster cards, the potential of the reader is limited by the cards rather than the reader or USB bus. But they’re what I’ve got, so that’s what I’m going with.

The Challenger

If we’re going to have a fight, lets have one against a worthy opponent. This was my mainstay card reader prior to the upgrade to USB3.0 – this is the Transcend USB2.0 card reader. It definitely was no slouch – in fact, I found it to be one of the fastest readers I have ever owned – pretty much matching a Delkin Devices reader I bought later and far surpassing my older Sandisk branded reader.

Transcend USB2.0 Card Reader

It’s larger, it’s white coloured – and inside, it has a chipset from a different vendor –

Chipset USB2.0 Reader

It’s an Alcor AU6376 – I’ve never heard of them before, but this chip is fast. This one also boasts support for DMA modes (which one!?!) in CF4.0 and SDHC support, but no matter how fast, there will always be a USB2.0 bus in the way (35MB/s is the rough limit). But how fast is it compared to the USB 3.0 reader for my cards?


So, the challenge will be posed with HDTune Pro version 4.6 doing a read benchmark across the full surface with highest accuracy and 8Mb block size selected, and the average speed will be our metric of choice. This will give you a good idea of the time for a full-card download if you divide the capacity of the card by the average speed.

The graphs will be provided – left will be USB 3.0 reader, right will be USB 2.0 reader.

Patriot LX 32Gb SDHC Class 10

PatriotLX-32Gb PatriotLX-32Gb-USB2

Team 32Gb SDHC Class 10

Team-32Gb Team-32Gb-USB2

The speed step in this one is likely due to the card controller handling “empty” sectors faster than handling full sectors.

Samsung 32Gb SDHC Class 10

Samsung-32Gb Samsung-32Gb-USB2

Kingston 2Gb SDSC Unclassed

Kingston-2Gb Kingston-2Gb-USB2

Lexar 16Gb 200x CF

Lexar-16Gb Lexar-16Gb-USB2

A-Data Speedy 8Gb CF

AData-8Gb AData-8Gb-USB2


Card USB 3.0 USB 2.0 Improvement (%) Time Saved per 32Gb Download (s)
Patriot LX 32Gb SDHC Class 10 21.8 19 14.73684211 221.5123
Team 32Gb SDHC Class 10 25.9 19.1 35.60209424 450.4283
Samsung 32Gb SDHC Class 10 22.1 19.1 15.70680628 232.8872
Kingston 2Gb SDSC Unclassed 13.5 12.6 7.142857143 173.3757
Lexar 16Gb 200x CF 45.8 18.9 142.3280423 1018.298
A-Data Speedy 8Gb CF 17.4 17.4 0 0


So it’s clear that we see the USB 3.0 card reader is no worse than the USB 2.0 card reader. What a relief. At a price of $29, it was a bargain, and so far it has been compatible with all the cards I use. The main limiting factor was really the speed of the cards themselves – if you have UHS-I or faster UDMA cards, the difference between USB 3.0 and USB 2.0 readers would have been more dramatic (e.g. in the CF results). UHS-I and UDMA cards have been seen to perform at 65-95MB/s or even more. But even so, the time saved per 32Gb download is about 3-4 minutes in most cases (for my cards – your mileage will definitely vary!) – it’s better than nothing, but it’s not entirely significant. But I guess there’s no reason not to get a USB 3.0 reader at this price. If you’re interested, benchmark your reader and see – you might surprise yourself how slow your reader is!

About lui_gough

I'm a bit of a nut for electronics, computing, photography, radio, satellite and other technical hobbies. Click for more about me!
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One Response to Transcend RDF8 USB 3.0 Card Reader

  1. abc says:

    works wonderfully, using firmware ts22

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