Hi fellow mac lovers,
My new Air/Thunderbolt system is great but I just noticed that USB transfer rates through the Thunderbolt Display are much slower!
Same disk drive, same cable, same file, same copy command:
USB thru Thunderbolt: ~0.5 GB / minute
USB from MacBook Air: ~2.0 GB / minute
Anyone else able to reproduce this phenomenon?
Thanks for checking,
William
As with any connection it is limited by it's weakest link. USB is by far the slowest connection so that will be your bottleneck. If the device that currently has a USB connection has any other connection types (Firewire, FW 800 or Thunderbolt) then speeds should dramatically improve by using one of those connections.
Hi William,
I just tried it and I get about the same speed for the TB Display and my Mac Mini. In both cases around 2GB/minute.
Mario
Your reply does not address my issue. I stipulate that firewire and thunderbold are faster than USB. What I'm noticing is that at least one of the USB ports on the back of my Thunderbolt display is running at about 1/4 the speed of the USB port which is built in to my MacBook Air.
Thanks for trying this, Mario. It looks like your display doesn't demonstrate the problem when used with the Mac Mini.
My TBD also displays this problem. For example, copying a 1.5GB file to a drive connected to one of the TBD usb ports takes 107 seconds, while doing the same thing using one of the MBA usb ports takes 50s.
Has anyone tested the speed of the TD USB ports? I find that while the Firewire 800 off the Thunderbolt Display is fast, the USB ports off the display run at about 1/4 of the speed of the USB ports on the MBA, copying the same 3.1 GB file:
These are the numbers I get.
| Port | 1.5G, write | Xbench |
| Tbd-fw | 79MB/s | 56 |
| Ext. usb hub | 25MB/s | 47 |
| MBA usb port | 34MB/s | - |
| Tbd-usb (right) | 15MB/s | 35 |
| Tbd-usb (center) | 14MB/s | - |
| Tbd-usb (left) | 15MB/s | - |
Best wishes,
Manuel
I forgot to mention that the TBD-USB read speeds are much better. I get about 33MB/s when copying the file from the drive (connected to the TBD-USB) to MBA SSD. I believe this speed is typical for a fast usb device (261 Mbps, about half the protocol maximum of 480Mbps).
So maybe it's a one-way problem...? I'll test that by tomorrow.
Thanks,
William
Yes, it may be mostly slow writting. However, a 15MB/s write speed is not that slow. A typical low-cost flash drive, for example, is even slower (5-6MB/s when writting; reading they can achieve 15MB/s). Since in general reading data is more frequent that writting it, I guess that we are "lucky" that our TBD's reading speed is good. Nevertheless, given the bandwidth available from the thunderbolt interface and the device price, it makes no sense for Apple to use a low-performance usb controller in the display. So I guess there is some sort of problem, either in hardware or firmware. If it is a firmware bug then we may see a fix in a future release. Also, if this is only happening with the MBA, then I guess it may be a bug in the notebook's firmware.
Regards,
Manuel
I agree. Here's my results:
By the way, I have the Thunderbolt Display Firmware version 1.0 and Thunderbolt Software Update version 1.1 installed.
And also noting that the speed from the MBA to external disk has just about doubled by installing the Thunderbolt Software Update version 1.1. Other speeds didn't change much.
Hey Mario, did you test both directions? I've found that reading from the external disk thru TBD USB is fast, but writing to external disk thru TBD USB is slower.
William
My comment above was incomplete. Here's the revision: "And also noting that the speed from the MBA to external disk thru TBD USB has just about doubled by installing the Thunderbolt Software Update version 1.1. Other speeds didn't change much."
Thunderbolt USB slow?
