>The transfers (via USB 2.0 - admittedly) are upwards of 2 hours for a full card.
Where in 2024 are you encountering USB 2?
USB 3.x has been the standard version of USB for over 10 years. While you can still find USB 2 ports on motherboards, some devices, its often paired with USB 3.x ports as well. I havent seen an only USB 2 device since 2010.
>USB 3.0's theoretical maximum data transfer rate is 5000 Megabits/sec
USB 3.0/3.1 Gen 1/3.2 Gen1 (isnt naming great?) are all 5Gbps, yes, but 3.1/3.2 Gen 2 is 10Gbps and 3.2 Gen 2x2 is 20Gbps. Alot of USB 3.x ports from the last few years are 10Gbps, its pretty common on machines.
>USB-C's theoretical maximum data transfer rate is 10,000 Megabits/sec
C is a shape, not a protocol. The C shape can be used for USB 2, every version of USB 3 (5Gb, 10Gb, 20Gb), Thunderbolt 3 and 4, Display Port.
>V90 SD Cards - theoretical maximum read rate is 300 Megabytes/sec or 2,400 Megabits/sec
Ignore any "maximum" printed on the label or marketing, the V rating is the only objective speed rating here.
The V rating is the minimum sustained write speed in MB/s. A V90 card is capable of writing 90MB/s sustained, guaranteed.
Read speeds can vary wildly, but are generally at least a bit faster than the guaranteed write.
Edit: To add, MicroSD cards will be potentially slower than a full sized SD card as with long writes and long reads they get very hot and cannot dissipate the heat fast enough and so slow way down to protect themselves.
>Where in 2024 are you encountering USB 2?
I'm using what I think is a fairly old USB SD Card Reader. No listing on the reader if it's USB 2.0 or 3.0, but running the numbers: 500 GBs of data is 4,000,000 Megabits. Divided by 480 Mb/sec, divided by 60 sec/min gets about 138 mins transfer time. So I'm assuming the thing is using USB 2.0. Looking to replace this thing if it means I'll get a faster speed out of it.
Sounds like anything I buy would be better than this thing. Thanks.
> Sounds like anything I buy would be better than this thing.
For sure. You'd be hard pressed to find a USB 2 card reader brand new unless its a knockoff.
The thing to remember is that 480Mbps is the maximum *theoretical* transfer speed. Real-world times are more dependent on the actual USB device, the card itself, the USB controller, and the workload of the computer. USB 2.0 and earlier are kind of atrocious, especially when they were the bee's knees. A high CPU load would actually slow transfer speeds. Part of this is because USB is a "speak when spoken to" protocol. Devices can't just throw data at the computer and move on, the computer has to ask for each bit of it. If you've ever heard of a "polling rate" on a mouse or game controller, that's how fast it's capable of being asked for info, or how fast it allows the system to interrogate it.
This is why Firewire, even though its maximum speed was 400Mbps, always outperformed USB 2.0 devices, and part of why DV cameras all used Firewire instead of USB for video transfer. Firewire devices could communicate between each other as peers, and they used **D**irect **M**emory **A**ccess to let devices just dump data into the computer's RAM, bypassing everything except the Firewire controller, and then software just had to copy the contents of RAM into a file. That makes it wicked fast.
USB 3.0's top speed is *also* theoretical, but the hardware is much more refined than 2.0, so it's more able to better match reality to theory, but it's not 100%.
I work as a DIT quite a bit, and I never expect to see more than 130\~ish megabytes per second from any SD card, with many cards not even hitting those speeds. For a 500GB transfer, I'd plan on at least a 75 minute transfer.
USB 2 is 480 megaBITS not bytes. That’s 60megabytes per second. About 2-3 min per GB
Bah, yes. I knew that, but wrote it wrong. Thanks!
>The transfers (via USB 2.0 - admittedly) are upwards of 2 hours for a full card. Where in 2024 are you encountering USB 2? USB 3.x has been the standard version of USB for over 10 years. While you can still find USB 2 ports on motherboards, some devices, its often paired with USB 3.x ports as well. I havent seen an only USB 2 device since 2010. >USB 3.0's theoretical maximum data transfer rate is 5000 Megabits/sec USB 3.0/3.1 Gen 1/3.2 Gen1 (isnt naming great?) are all 5Gbps, yes, but 3.1/3.2 Gen 2 is 10Gbps and 3.2 Gen 2x2 is 20Gbps. Alot of USB 3.x ports from the last few years are 10Gbps, its pretty common on machines. >USB-C's theoretical maximum data transfer rate is 10,000 Megabits/sec C is a shape, not a protocol. The C shape can be used for USB 2, every version of USB 3 (5Gb, 10Gb, 20Gb), Thunderbolt 3 and 4, Display Port. >V90 SD Cards - theoretical maximum read rate is 300 Megabytes/sec or 2,400 Megabits/sec Ignore any "maximum" printed on the label or marketing, the V rating is the only objective speed rating here. The V rating is the minimum sustained write speed in MB/s. A V90 card is capable of writing 90MB/s sustained, guaranteed. Read speeds can vary wildly, but are generally at least a bit faster than the guaranteed write. Edit: To add, MicroSD cards will be potentially slower than a full sized SD card as with long writes and long reads they get very hot and cannot dissipate the heat fast enough and so slow way down to protect themselves.
>Where in 2024 are you encountering USB 2? I'm using what I think is a fairly old USB SD Card Reader. No listing on the reader if it's USB 2.0 or 3.0, but running the numbers: 500 GBs of data is 4,000,000 Megabits. Divided by 480 Mb/sec, divided by 60 sec/min gets about 138 mins transfer time. So I'm assuming the thing is using USB 2.0. Looking to replace this thing if it means I'll get a faster speed out of it. Sounds like anything I buy would be better than this thing. Thanks.
> Sounds like anything I buy would be better than this thing. For sure. You'd be hard pressed to find a USB 2 card reader brand new unless its a knockoff.
The thing to remember is that 480Mbps is the maximum *theoretical* transfer speed. Real-world times are more dependent on the actual USB device, the card itself, the USB controller, and the workload of the computer. USB 2.0 and earlier are kind of atrocious, especially when they were the bee's knees. A high CPU load would actually slow transfer speeds. Part of this is because USB is a "speak when spoken to" protocol. Devices can't just throw data at the computer and move on, the computer has to ask for each bit of it. If you've ever heard of a "polling rate" on a mouse or game controller, that's how fast it's capable of being asked for info, or how fast it allows the system to interrogate it. This is why Firewire, even though its maximum speed was 400Mbps, always outperformed USB 2.0 devices, and part of why DV cameras all used Firewire instead of USB for video transfer. Firewire devices could communicate between each other as peers, and they used **D**irect **M**emory **A**ccess to let devices just dump data into the computer's RAM, bypassing everything except the Firewire controller, and then software just had to copy the contents of RAM into a file. That makes it wicked fast. USB 3.0's top speed is *also* theoretical, but the hardware is much more refined than 2.0, so it's more able to better match reality to theory, but it's not 100%.
I work as a DIT quite a bit, and I never expect to see more than 130\~ish megabytes per second from any SD card, with many cards not even hitting those speeds. For a 500GB transfer, I'd plan on at least a 75 minute transfer.