microSD SD card vs USB adapters, same thing?

[tinpanalley]

Is there any difference in speed copying to a microSD card using a microSD-USB adapter or a microSD-SD card adapter? What speed does an SD reader slot on a front desktop panel even get to? Because I'm wondering if a USB3.0-microsd card reader wouldn't be the fastest option.
Thoughts?

 

[Elixer]

You would be limited by the SD card's speed, not the USB3 interface.

 

[tinpanalley]

You would be limited by the SD card's speed, not the USB3 interface.

So it's safe to say that a fast microSD (Class-10, UHS-3) will write at the same speed regardless of whether you use a microSD-full SD adapter or whether you put it in a microSD-USB3.0 adapter?

 

[Elixer]

So it's safe to say that a fast microSD (Class-10, UHS-3) will write at the same speed regardless of whether you use a microSD-full SD adapter or whether you put it in a microSD-USB3.0 adapter?

Yup.

 

[paperwastage]

again, no such thing as UHS-3

there's UHS-1 and UHS-2. This is the bus (transfer) speed.

You can see the extra pins for UHS-2, that allow for higher transfer speed. Backward compatible with UHS-1 card readers (slows down to UHS-1 speeds). Useful when transferring data to a computer (eg: copy 50GB of raw photo, higher read speed = useful)
https://www.sdcard.org/developers/overview/bus_speed/



U3 = speed class. This guarantees a minimum sequential write speed, typically to make sure you can record 100mbps 4K video (100mbps = 12.8MB/s, U1 = 10MB/s write isn't enough, need U3)
https://www.sdcard.org/developers/overview/speed_class/index.html

There are new speed classes available - V30, V60, V90, again for minimum sequential write speed (typically for 4K or higher video recording)
https://www.sdcard.org/consumers/choices/speed_class/index.html





that saying, as long as the card reader (SD card reader, or microSD->USB card reader) is of the same type "UHS-1" and SD card doesn't do UHS-2, then you're fine*. otherwise, a UHS-2 card reader would be useful

*my laptop uses PCIe bus for SD card reader, which would have lower latency/issues than a USB(3) card reader. your front panel likely is USB only

 

[Insert_Nickname]

IWhat speed does an SD reader slot on a front desktop panel even get to?

That'll depend on the reader in question. It can be either USB2 or USB3.

Simplest way to check is what internal socket type it uses. 9-pin is USB2, 19-pin is USB3.

Because I'm wondering if a USB3.0-microsd card reader wouldn't be the fastest option.

That depends on the type of card in question. But generally, yes. A USB3 reader supporting UHS-2 will be the fastest* solution for all card types.

I've had good results with this basic SanDisk one:
https://www.sandisk.com/home/memory...ers/extremepro-sdhc-sdxc-uhs-ii-reader-writer

*unless you count the really extreme PCIe interface card readers. But those tend to be costly.

 

[tinpanalley]

again, no such thing as UHS-3

"Again"? Had you said it before? And also, yes actually there is "UHS Speed Class 3". What there isn't is "UHS-III" when referring to bus which I didn't clarify in my post, but I thought it was clear. The one DEFINITELY clear thing is how dumb it was for Secure Digital to use the same letter for two different specs. Stupid.

You can see the extra pins for UHS-2, that allow for higher transfer speed. Backward compatible with UHS-1 card readers (slows down to UHS-1 speeds).

I'll have a look at my internal card reader. The manual doesn't say anything specswise. Thanks for the reply and advice.

 

[paperwastage]

well, i say "again" because I keep seeing this mess... hate/blame SD for this. wonder if my head will explode if they came out with UHS-III bus speed

sorry if it sounded rude


and they decided to "extend" UHS Speed class to Video speed class
V6 (which no one really cares about), V10, V30, V60, V90... sigh. at least U is different from V, but they're visually similar

 

[Elixer]

Sorry, I should have been more clear, it does depend on the internal reader and what that is hooked up to. So, a USB 3 reader can perform better than a built-in reader that doesn't use the fastest interface it has available to it, BUT, to make things more complicated, it also depends on the USB 3 reader itself. Some are limited to UHS-I.

 

[tcsenter]

Is there any difference in speed copying to a microSD card using a microSD-USB adapter or a microSD-SD card adapter? What speed does an SD reader slot on a front desktop panel even get to?

SD-USB 'adapter' is going to be just a USB card reader with it's own controller/processor. It's not really an "adapter" it's a device reader. The mSD-SD adapter is a true adapter and doesn't have any controller.

 

[tinpanalley]

SD-USB 'adapter' is going to be just a USB card reader with it's own controller/processor. It's not really an "adapter" it's a device reader.

Well, what I have is literally a USB2.0 stick with nothing more than memory card slots on it. I'm not talking about a mini hub with a USB cable on the back. But maybe that's the same thing.
However, I do have one of those that IS USB3.0 as well.

 

[tinpanalley]

In case anyone's interested... some numbers using CrystalDiskMark 5
All tests, Sequential 500MiB only because I thought that I usually send one or two albums at a time over to my microSD when copying music to it. Each album is on average about 250MB. This is a rough estimate test.

Note: the SanDisk adapter and the USB adapter are plugged into a USB3.0 port in my front panel internal reader that I only really bought for the 2USB 3.0 ports and eSATA. I don't care about slow transfer of regular files. I bought and installed this thing because I needed two USB3.0 ports and an eSATA facing forward on my tower and because it's usually for files which don't matter speed-wise. I just want the music and videos to transfer quickly which is why I'm trying to figure that out with this test.

1. SanDisk microUSB-USB adapter (note: this is the kind that comes with any microSD card)
Read: 32.50
Write: 31.46

2. Transcend USB3.0 UHS-I Card Reader
Read: 71.93
Write 52.85

3. ioGear USB Card Reader
Read: 10.07
Write: 19.29

Clearly there's a big difference. And the USB 3.0 card reader is best for speed. And I'm getting the "UP TO" 40MB/S write speed that SanDisk are advertising for the Extreme 16GB U3 in more than one device but how exactly are they getting the "UP TO" 90MB/s read speed? Yes, yes, I know, "performance may be lower depending on host device, interface, usage conditions and other factors." so I'm just wanting to learn here, what am I not testing that they are?

 

[Insert_Nickname]

Clearly there's a big difference. And the USB 3.0 card reader is best for speed. And I'm getting the "UP TO" 40MB/S write speed that SanDisk are advertising for the Extreme 16GB U3 in more than one device

One reason to prefer USB3 is that, unlike USB2, it is full-duplex. With USB2 you can only read/write in one direction at a time. Think updating the file table f.x.

but how exactly are they getting the "UP TO" 90MB/s read speed? Yes, yes, I know, "performance may be lower depending on host device, interface, usage conditions and other factors." so I'm just wanting to learn here, what am I not testing that they are?

I always treat "up to" ratings as "under absolutely ideal theoretical conditions". A good rule of thumb is to expect half of claims in real-world conditions.

I have a particular Kingston UHS-1 (U3) card, that can actually get pretty close (80MB/s read) to its rated transfer (90MB/s), but I consider that more of a fluke then representative.

 

[tweakboy]

Nope!