UHS-I vs UHS-II USB-C SD Card Readers: Which Should You Buy?
By The Gear Audit Team | Research checked October 13, 2026
The quick buying answer
Choose a UHS-II reader when you use UHS-II SD cards and frequent, large imports make waiting a problem. The SanDisk Extreme PRO SD UHS-II USB-C Reader/Writer, SDDR-409, fits that job. For ordinary UHS-I cards and a mix of full-size SD and microSD, the Anker USB-C 2-in-1 Card Reader, A8370, offers a more useful slot arrangement.
Keep a satisfactory existing reader if imports are already convenient. A new reader cannot make your camera shoot faster, and USB-C describes the connector rather than the card interface or the speed you will actually get.
Choose for the cards you actually import
A reader purchase should solve a specific friction: a missing card slot, awkward microSD adapters or time spent copying a large shoot. Start by looking at your cards and timing one normal import with your existing setup. That gives you a useful baseline without assuming a product’s advertised maximum is your current bottleneck.
Consider Anker A8370 when direct SD and microSD slots suit your kit. UHS-II capability alone will not turn a UHS-I card into a UHS-II card. If your current reader already works well, changing it solely for the Roman numeral brings an uncertain benefit.
Consider SanDisk SDDR-409 to give those cards a matching interface. This is the more appropriate of these two examples for removing a UHS-I reader from a UHS-II offload route. The time saved still depends on the card and computer.
The Anker’s dedicated microSD slot avoids an SD adapter for that second card format. The SanDisk uses a full-size SD slot; its manufacturer permits microSD with an adapter. Choose around the format you handle most often.
Check its documented UHS support and test a typical copy before adding hardware. An external reader is worthwhile if it solves compatibility, access or import time. It is an extra item to carry when none of those problems exists.
Two exact USB-C readers compared
| Buying detail | Anker USB-C 2-in-1 | SanDisk Extreme PRO SD |
|---|---|---|
| Exact model | A8370; current Anker Canada listing | SDDR-409; current US page lists SDDR-409-C46 |
| Card interface | UHS-I for both card slots | UHS-II; also accepts UHS-I and non-UHS SD cards |
| Card slots | One full-size SD and one microSD | One full-size SD; microSD needs an adapter |
| Computer connection | Direct USB-C plug; Anker advertises a 5Gbps connection | USB-C plug on a short flexible lead; USB 3.0 interface |
| Most useful distinction | Two card formats without an SD adapter for microSD | UHS-II support for compatible SD-card imports |
| Main reason to choose something else | You want UHS-II transfers from UHS-II SD cards | You mainly need direct microSD access or your existing UHS-I setup is sufficient |
| Measured transfer result here | Not measured | Not measured |
Specifications: Anker Canada A8370 product page, Anker’s card-slot specification and SanDisk SDDR-409 product page. Connection ratings are not measured card-copy speeds. Photos are not a size comparison.
Anker A8370: for SD and microSD convenience
Best for: A photographer who imports UHS-I SD cards and also handles microSD, with a compatible USB-C host.
The A8370 is a practical format choice when your bag contains both kinds of card. A direct microSD slot means one fewer adapter to find during an import. Anker also describes simultaneous access to the two differently sized cards; that should not be read as a guarantee that both transfers reach a maximum speed together.
Pros
- Direct access to two card formats: Convenient for a camera-plus-action-camera kit.
- Simple travel setup: The integrated USB-C plug avoids packing a separate reader cable.
- Fits a UHS-I workflow: A sensible shortlist option when slot access matters more than adding UHS-II capability.
Cons
- UHS-I ceiling on the card side: This is the wrong purchase if the goal is UHS-II offloading.
- Fixed placement at the socket: Check your computer’s port spacing and any phone-case opening. A short-lead reader lets you position the card slot away from the device.
- No USB-A connection: If USB-A is the available port, choose a suitable reader for it rather than assuming USB-C will fit.
Our recommendation
Choose A8370 for useful SD/microSD access with UHS-I cards. Choose the SanDisk instead if UHS-II SD imports are the reason for upgrading. For phone or tablet use, verify the exact device’s USB storage support, file app and card format; the presence of a USB-C socket is only the first check.
This is a model search, not a verified US offer. Research used the current Canadian manufacturer listing. Confirm the model, pictured exterior, supported cards and seller; do not confuse it with Anker’s USB-A/USB-C reader models.
SanDisk SDDR-409: for UHS-II SD offloading
Best for: Regular imports from UHS-II SD cards where the reader is currently limiting the connection.
The reason to shortlist this reader is its UHS-II card interface. It can give a UHS-II card a suitable offload route even if the camera that recorded the files used a slower card interface. The files do not have to have been recorded at UHS-II speed to be read through a UHS-II connection later.
Pros
- Matches UHS-II SD cards: The relevant capability for a photographer upgrading a UHS-I import route.
- Retains older SD-card compatibility: You can keep using UHS-I and non-UHS SD cards as well.
- Flexible lead: Lets the reader sit away from the computer socket, which can make inserting cards easier.
Cons
- One card slot: It does not provide the Anker’s separate SD and microSD access.
- microSD requires an adapter: Less convenient if small cards dominate your routine; check the adapter’s compatibility with your card.
- Benefit depends on your workflow: A small occasional import or a slower destination drive may leave little reason to replace an adequate reader.
Our recommendation
Choose SDDR-409 when UHS-II SD offloading solves an actual waiting problem. Keep a capable existing reader if copying is already convenient. If you need CFexpress, XQD or another card format, buy a reader explicitly made for that format; these SD slots do not serve those cards.
Search Amazon for SanDisk SDDR-409
Confirm SDDR-409 and USB-C in the listing. Regional suffixes differ: the current US manufacturer page lists C46, while a G46 URL is also indexed. This search does not establish a specific retail suffix, ASIN, stock status or offer.
Four limits that matter more than the USB-C shape
1. The SD bus is a capability, not your copy result
The SD Association describes UHS-II’s second row of contacts and bus modes up to 312MB/s. Its bus-speed chart lists standard UHS-I at up to 104MB/s. Those are interface limits, not measured sustained speeds for either reader here. Anker’s 5Gbps label refers to the USB connection; it does not promise a card will read at 625MB/s.
There is an important exception to simplistic UHS-I limits: some manufacturers use proprietary faster modes. SanDisk’s QuickFlow documentation requires compatible equipment for speeds beyond standard UHS-I. Do not assume either selected reader can deliver a card’s above-104MB/s headline without exact card-and-reader support.
2. Card read speed and camera write requirements are different
For importing, look at the card’s documented read capability and the reader interface. For recording, follow your camera’s exact card requirements, including its slot, capacity and supported recording modes. The U3 and V30/V60/V90 marks describe minimum sequential writing classes, not an import-speed ranking. UHS-II support alone does not make a card suitable for every high-bitrate camera mode.
A reader connects after the shoot. Replacing it cannot change the camera’s card interface, buffer clearing or video recording limits. Conversely, a camera’s UHS-I limitation does not automatically remove the offload benefit of a UHS-II card used later in a UHS-II reader.
3. The host and destination remain part of the route
USB-IF treats USB-C connector naming and performance as separate matters. Check the computer’s actual port speed, plus any hub in between. A slower connection can hold back a capable reader. When diagnosing an import, connect directly to an appropriate host port first so a hub is not an extra variable.
The receiving drive must also write the files, and import software may spend time generating previews or processing images after the copy. If you copy to an external SSD, check that drive and its connection too. Our Samsung T7 Shield vs T9 guide explains why a faster drive label needs a matching host.
4. A large sequential copy is only part of a photo import
A long video file and thousands of photographs are different workloads. File overhead, card condition, software and preview settings can all affect the wait. Compare the same representative folder, same destination and same import settings when assessing an upgrade. If the copy finishes quickly but previews take much longer, investigate that stage before buying a reader.
A short checklist before you buy
- Identify the card. Read its exact model, format and UHS mark. For shooting requirements, use your camera manual rather than a reader’s product description.
- Identify the host route. Check the USB port or built-in reader specification. Include the hub if you intend to leave one connected.
- Find the waiting stage. Distinguish file copying from software import and preview generation. Use your present setup as the baseline.
- Match the physical format. Decide whether direct microSD access, a flexible lead or another card format matters. Neither example adds charging or replaces a full USB hub.
- Check the actual listing. Match A8370 or SDDR-409, USB-C, card support and included accessories. Search results can mix similar names, regional packages and other readers.
USB-C SD reader FAQ
Is a UHS-II reader worth it for a UHS-I card?
It may be useful for an upcoming UHS-II card or a better physical setup. UHS-II support by itself does not make a UHS-I card use the UHS-II bus. Check exact support for any proprietary faster UHS-I mode separately; do not buy on that assumption.
Does V90 mean 90MB/s read speed?
No. V90 is a minimum sequential write-speed class under the relevant standard conditions. It is not a promised import speed or the same thing as UHS-II. Camera compatibility and the exact card’s read specification are separate checks.
Will a faster reader improve my camera’s burst shooting?
No. The external reader handles files after recording. The camera’s own card slot, buffer, recording mode and card write performance determine shooting behavior. Choose cards according to that camera’s documentation.
Can I use these readers with a phone or tablet?
Check the exact host’s USB storage support, available file app, supported card file system and physical fit. Anker describes compatible USB-C phone use, while SanDisk’s selected page specifies Mac and PC USB-C use. We have not established compatibility with every phone or tablet.
Should I plug the reader into a hub?
A compatible hub can be convenient, but its card interface and host connection need their own checks. Use a direct connection when investigating slow transfers. If your current hub’s reader already does the job, an additional reader may add little value.
Related buying guides
- Mirrorless cameras by shooting need — choose the camera before planning its card workflow.
- How to choose a USB-C hub — check the host route when adding peripherals.
- Samsung T7 Shield vs T9 — match an external import destination to its USB connection.
Research method, primary sources and limits
We checked manufacturer pages and standards guidance on October 13, 2026. Product capabilities are manufacturer claims; our recommendations interpret them for buying scenarios. We did not conduct card-copy, camera-buffer, import-time, reliability or durability tests. There is no measured speed winner here.
Reader sources: Anker Canada A8370 product page and product photo; Anker UHS-I slot specifications; Anker A8370 model declaration; current SanDisk SDDR-409 specifications and photo; SanDisk SDDR-409 support identity.
Standards and transfer caveats: SD Association bus interfaces; SD Association write-speed classes; USB-IF naming and performance guidance; SanDisk QuickFlow compatibility caveat.
The Anker source is regional; its current gray product photo does not establish a US retail SKU. SanDisk regional suffixes are not treated as interchangeable verified offers. Both buying buttons are labelled model searches. No static prices, numerical ratings, review counts or ASINs are claimed. See our methodology.
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