usb3 vs thunderbolt ?

[dseelig]

Okay say I have got 50 gb of data to transfer how mcuh faster will it be over thunderbolt then usb 3 for backing up? I am talking in practice not theory. PS with a 7200 rpm hd in both
thanks David

[BobShaw]

Well USB3 is 5Gb/S and Thunderbolt is 20Gb/S. Actual performance is going to depend on a lot of things.
If you are transferring data then the transmit speed is the same as the receive speed at the other end.
Backing up is different to transferring. There is a whole lot of smarts going on as well as just transferring.
With Thunderbolt you can also daisy chain drives. With USB you need a port for each or you need hubs.
It is probably fair to say Thunderbolt will be faster if you let it.

[Miles]

Bob is correct regarding the speed of thunderbolt2 vs usb3.  The limiting factor however, will be the read/write speed of the drive, which is probably below the USB3 through put speed.  Thus, you will never obtain the maximum transfer rate of either thunderbolt or usb if just copying a hard drive.  Copy time will probably be very similar between the two under the scenario you describe.

Thunderbolt has other advantages, but those were not part of your question.

Miles

[E.J. Peiker]

It's essentially a dead heat.  As stated, it's the actual drive that limits the throughput.  here is a comparison that MacWorld did and as you can see from the table, there is essentially no difference:
http://www.macworld.com/article/2039427/how-fast-is-usb-3-0-really-.html

[sbay]

I have OWC's 4bay thunderbolt enclosure and it's pretty fast -- it's not limited by drive speed even in a multi drive RAID stripe.

Not sure where a USB3 RAID would top out, but from the article above USB3 never got over 200 Mbps which can be exceeded by a 2 drive stripe.

[davidgp]

If I understood correctly, the original poster says the he is putting an 7200 RPM drive connected to USB3 or Thunderbolt, then the difference is 0, the drive it is the limiting factor here.

The macworld article referenced above it is wrong. They did not tested an USB 3 drive with support for UASP ( http://en.wikipedia.org/wiki/USB_Attached_SCSI ). As you can read here: http://forums.macrumors.com/showthread.php?t=1712510 using a UASP enclosure with a typical SSD SATA drive you can get around 400 MB/sec for read and writing speed. USB3 overhead it is the limiting factor here, because those drives could easily reach 5XX MB/sec of read speeds (in this case the limiting factor it is the SATA bus, this is the reason Apple is mounting PCIe SSD drives in their laptops and some desktops). Here you have also a test using one unique drive: http://macperformanceguide.com/Reviews-OWC-EliteProDual-TB-USB3-Thunderbolt-vs-USB3.html where thunderbolt gets the same speed as USB3 (well, it is a RAID 0 configuration, so, practically it is just like one drive).

One unique SSD SATA drive connected to a Thunderbolt 1 or 2 it is not going to get better speeds than USB3, probably it could reach 5XX MB/sec but not much more, since the limiting factor it is, again, the SATA bus.

Now, if you buy a raid enclouse, and you put SSD drives on it, you can see here you can get around 800 MB/sec http://macperformanceguide.com/Reviews-OWC-Thunderbay-RAID.html . The limiting factor it is not the bus, thunderbolt, but probably the drives or the RAID controller of the enclosure (and it is using software RAID).

If you connect a thunderbolt PCIe enclosure with a PCIe solid state drive you will probably reach even bigger speeds... not sure if there it is too much offer.

[jduncan]

If I understood correctly, the original poster says the he is putting an 7200 RPM drive connected to USB3 or Thunderbolt, then the difference is 0, the drive it is the limiting factor here.

The macworld article referenced above it is wrong. They did not tested an USB 3 drive with support for UASP ( http://en.wikipedia.org/wiki/USB_Attached_SCSI ). As you can read here: http://forums.macrumors.com/showthread.php?t=1712510 using a UASP enclosure with a typical SSD SATA drive you can get around 400 MB/sec for read and writing speed. USB3 overhead it is the limiting factor here, because those drives could easily reach 5XX MB/sec of read speeds (in this case the limiting factor it is the SATA bus, this is the reason Apple is mounting PCIe SSD drives in their laptops and some desktops). Here you have also a test using one unique drive: http://macperformanceguide.com/Reviews-OWC-EliteProDual-TB-USB3-Thunderbolt-vs-USB3.html where thunderbolt gets the same speed as USB3 (well, it is a RAID 0 configuration, so, practically it is just like one drive).

One unique SSD SATA drive connected to a Thunderbolt 1 or 2 it is not going to get better speeds than USB3, probably it could reach 5XX MB/sec but not much more, since the limiting factor it is, again, the SATA bus.

Now, if you buy a raid enclouse, and you put SSD drives on it, you can see here you can get around 800 MB/sec http://macperformanceguide.com/Reviews-OWC-Thunderbay-RAID.html . The limiting factor it is not the bus, thunderbolt, but probably the drives or the RAID controller of the enclosure (and it is using software RAID).

If you connect a thunderbolt PCIe enclosure with a PCIe solid state drive you will probably reach even bigger speeds... not sure if there it is too much offer.

Hi, Agree, just a detail, you don't need to use SSDs to get and advantage with thunderbolt2.  High density HD will do, if they are plenty.  All equal  (cache and RPM) a higher capacity HD will be faster than lower capacity ones.  This is due to a couple of factors: Superior density and the fact that we are storing actual data and not doing testing. That means that if you can place all your information on an 6TB the higher density array will have more empty (and fast) space.  The risk is related to rebuild times.

In testing Thunderbolt2 will surpass the max theoretic speed of usb 3.0 with HD. What you could gain with with SSDs is random access performance but bandwidth  will be limited by thunderbolt.

Even the tinny 30TB Lacie  5big thunderbolt 2 will pass 8Gbit/s (vs 5Gbit/s USB max).

Best regards

[Christopher]

I would say Thunderbolt has some advantages in speed. However, I choose a USB3 SSd for external usage. I can reach 430 MB/s, which is quite fast enough. The big advantage with USB is, I can ise it with every computer I own, even if it's an older one with only USB2. As long as Thunderbolt is so limited in available hardware, I do not see much sense spending so much money on it.

[BJL]

Some good news for the future: Thunderbolt 3 will incorporate USB 3.1, and use the new USB-C plug and socket, so it looks like a promising unification.