USB 2.0 vs. USB 3.0: Speed Comparison for Flash Memories and External HDDs

In summary: Nowadays, most devices have some form of over-the-air software update that increases the available bandwidth.No, it is the communication device's bandwidth. Some devices (old dial-up modems come to...mind) would use a fixed amount of bandwidth that couldn't be increased no matter how much data was being transferred. Nowadays, most devices have some form of over-the-air software update that increases the available bandwidth.
  • #1
mech-eng
828
13
In flash memories or external HDDs there is a distinction as usb 2 or usb 3. USB 3.0 is faster than USB 2.0 in such devices. But what about the situation for SDD drives? Does this distinction apply to them, too?

Thank you.
 
Computer science news on Phys.org
  • #2
mech-eng said:
In flash memories or external HDDs there is a distinction as usb 2 or usb 3. USB 3.0 is faster than USB 2.0 in such devices. But what about the situation for SDD drives? Does this distinction apply to them, too?

Thank you.
USB is a transfer mechanism. Any device that is capable of send/receive at USB3 speeds will be faster with USB3 than with USB2. It's irrelevant what KIND of device it is; it only matters what its transfer rates are. A device that can only send/receive at USB2 speeds will be no faster with USB3 than with USB2.
 
  • Like
Likes QuantumQuest and mech-eng
  • #3
mech-eng said:
But what about the situation for SDD drives?
Do you mean SSD (solid state drives)?
 
  • Like
Likes mech-eng
  • #4
jtbell said:
Do you mean SSD (solid state drives)?

Yes, a mistake. I thought they were solid state disk drive, but not.

Thank you.
 
  • #5
The SSD is capable of bandwidth way higher than both USB 2 and 3. You will be limited by your connection, not the drive. I would highly recommend properly connecting it via a SATA connector.
 
  • Like
Likes mech-eng
  • #6
newjerseyrunner said:
The SSD is capable of bandwidth way higher than both USB 2 and 3.

But isn't there a relation between bandwitdth and connection types, i.e USB types?

Thank you.
 
  • #7
mech-eng said:
But isn't there a relation between bandwitdth and connection types, i.e USB types?

Thank you.
Absolutely not. That's like saying that the size of your water tank depends on how big your faucet opening is. The SSD has a much higher bandwidth than the USB2 or even USB3 connections and if you have a faster connection, it will handle it. Conversely, if you have a very slow external drive, hooking it up to a USB3 won't make it any faster.
 
  • Like
Likes jim mcnamara and mech-eng
  • #8
newjerseyrunner said:
The SSD is capable of bandwidth way higher than both USB 2 and 3. You will be limited by your connection, not the drive. I would highly recommend properly connecting it via a SATA connector.
Or better still, connect a SSD to the PCIe bus. Seagate makes PCIe SSD's with up to 8GB/s transfer rates.
 
  • Like
Likes newjerseyrunner and mech-eng
  • #9
phinds said:
Absolutely not. That's like saying that the size of your water tank depends on how big your faucet opening is. The SSD has a much higher bandwidth than the USB2 or even USB3 connections and if you have a faster connection, it will handle it. Conversely, if you have a very slow external drive, hooking it up to a USB3 won't make it any faster.

Then can we say that the bandwidth somebody can use is the lower one between the device and the connection type for the device and the PC? If the SSDs have a higher bandwidth than the all connection types, are SSDs using connections at a speed of connection's full speed?
 
  • #10
mech-eng said:
Then can we say that the bandwidth somebody can use is the lower one between the device and the connection type for the device and the PC?
yes
If the SSDs have a higher bandwidth than the all connection types, are SSDs using connections at a speed of connection's full speed?
Not sure I understand the question, but if I do then yes, ANY device will attempt to communicate at the highest speed possible, but that may not be a continuous function, depending on the device and the connection. Some devices (I don't think SSD's are among them) are set to communicate at discrete bandwidths. (at least that used to be the case. I'm not really up on modern communications technology)
 
  • Like
Likes mech-eng
  • #11
phinds said:
Not sure I understand the question, but if I do then yes, ANY device will attempt to communicate at the highest speed possible, but that may not be a continuous function, depending on the device and the connection. Some devices (I don't think SSD's are among them) are set to communicate at discrete bandwidths. (at least that used to be the case. I'm not really up on modern communications technology)

When transfering data via usb, windows can shows the speeds. In my cases, the speeds are not constant, they are frequently changing between a maximum value and a minumum value. Why is this the case? What is "discrete bandwidths"? Isn't a discrete bandwidth you used above is device's own bandwidth?

Thank you.
 
  • #12
mech-eng said:
When transfering data via usb, windows can shows the speeds. In my cases, the speeds are not constant, they are frequently changing between a maximum value and a minumum value. Why is this the case?
Because the computer (and possibly the computer on the device) will be doing other things in addition to the transfer.
What is "discrete bandwidths"? Isn't a discrete bandwidth you used above is device's own bandwidth?
No, it is the communication device's bandwidth. Some devices (old dial-up modems come to mind) would transfer at a fixed rate, but if that didn't work it would drop down to a lower rate. There would generally be a handshake between devices to agree on a rate.
 
  • Like
Likes mech-eng
  • #13
phinds said:
Because the computer (and possibly the computer on the device) will be doing other things in addition to the transfer.No, it is the communication device's bandwidth. Some devices (old dial-up modems come to mind) would transfer at a fixed rate, but if that didn't work it would drop down to a lower rate. There would generally be a handshake between devices to agree on a rate.

But there are two relevant devices, one is the storage which is pluged into the PC via a connection type and the other is connection type i.e the port and slots. Aren't we already discussing them and their bandwidths? So communication device's bandwidth is confusing to me. Would you please explain it?

Thank you.
 
  • #14
mech-eng said:
But there are two relevant devices, one is the storage which is pluged into the PC via a connection type and the other is connection type i.e the port and slots. Aren't we already discussing them and their bandwidths? So communication device's bandwidth is confusing to me. Would you please explain it?

Thank you.
This thread started off discussing USB transfer mechanisms. That is a communication device. You have STORAGE <-> USB <-> COMPUTER. The USB is the communication device.

https://en.wikipedia.org/wiki/USB_communications_device_class
 
  • Like
Likes mech-eng
  • #15
mech-eng said:
In flash memories or external HDDs there is a distinction as usb 2 or usb 3. USB 3.0 is faster than USB 2.0 in such devices. But what about the situation for SDD drives? Does this distinction apply to them, too?

Thank you.
The question raises some complexities. The terms must be clarified and qualified before they can be used to convey appropriately precise and unambiguous information. This brief (3 pages) HP paper on USB 3.0 clarifies some of the characteristics (please note that bandwidth is expressed in bits, while throughput is expressed in bytes). This full-length (145 pages) Intel paper on IO interface architecture has more scope and is more in-depth. And this SNIA (Storage Networking Industry Association) short (28 pages) SSD performance primer is reasonably rigorous without being too dry.
 
  • Like
Likes mech-eng and jim mcnamara

Related to USB 2.0 vs. USB 3.0: Speed Comparison for Flash Memories and External HDDs

What is the difference between USB 2.0 and USB 3.0?

The main difference between USB 2.0 and USB 3.0 is the data transfer speed. USB 3.0 is capable of transferring data at a much faster rate compared to USB 2.0. USB 3.0 also has more power output and is more power efficient than USB 2.0.

How much faster is USB 3.0 compared to USB 2.0?

USB 3.0 has a maximum data transfer speed of 5 Gbit/s, while USB 2.0 has a maximum speed of 480 Mbit/s. This means that USB 3.0 is approximately 10 times faster than USB 2.0.

Does the speed difference between USB 2.0 and USB 3.0 affect the performance of flash memories and external HDDs?

Yes, the speed difference between USB 2.0 and USB 3.0 can significantly affect the performance of flash memories and external HDDs. USB 3.0 allows for faster data transfer, which means that files can be copied or accessed much quicker compared to USB 2.0.

Are there any other benefits of using USB 3.0 for flash memories and external HDDs?

Aside from faster data transfer speed, USB 3.0 also has higher power output, allowing for faster charging of devices. It also has improved data transfer protocols, resulting in more reliable and stable connections.

Can USB 2.0 devices be used with USB 3.0 ports?

Yes, USB 2.0 devices can be used with USB 3.0 ports, but the data transfer speed will be limited to the maximum speed of USB 2.0. However, it is not possible to use USB 3.0 devices with USB 2.0 ports as they require the higher speed and power output of USB 3.0.

Similar threads

  • Computing and Technology
Replies
3
Views
1K
  • Computing and Technology
Replies
5
Views
966
  • Computing and Technology
2
Replies
36
Views
4K
Replies
11
Views
3K
  • Computing and Technology
Replies
12
Views
4K
  • Computing and Technology
Replies
14
Views
3K
  • Electromagnetism
Replies
4
Views
1K
  • Biology and Medical
Replies
5
Views
2K
Back
Top