5k imac USB3 port faster than Mac Pro, is it normal?

[Amethyst]

i have test my mac pro 2013 & imac 5K usb3 external disk performance using same drive (Transcend Storjet 25s3+intel 530 ssd peak (500/550mb)), and i found that mac pro is somewhat slower than iMac as shown in attached image.

is it normal?

 

[kennyman]

Checked the test file size, noticed:

nMP - 512 MB
iMac - 1 GB

I would suggest to run the test again with the same file size.

 

[filmak]

Checked the test file size, noticed:

nMP - 512 MB
iMac - 1 GB

I would suggest to run the test again with the same file size.

nice find, file size certainly makes a difference.

 

[Amethyst]

just change file size to 1GB, nothing change.

 

[chrfr]

i have test my mac pro 2013 & imac 5K usb3 external disk performance using same drive (Transcend Storjet 25s3+intel 530 ssd peak (500/550mb)), and i found that mac pro is somewhat slower than iMac as shown in attached image.

is it normal?

The 2013 Mac Pro has hardware limitations on USB 3 performance. It's not surprising that the iMac is faster as with that computer, USB 3.0 is integrated into the chipset.
http://macperformanceguide.com/MacPro2013-USB3-performance-limitations.html
http://www.anandtech.com/show/7603/mac-pro-review-late-2013/8

 

[Joe The Dragon]

The mac pro is also at the limits of PCI-E moving usb 3 to the chipset will not help that much as the chipset DMI link is only pci-e 2.0 or 3.0 X4.

 

[ActionableMango]

is it normal?

I assume so. I've seen similar results with my 2010 MP and a 2012 Mini. The Mini is a little bit faster.

And I'm even seeing the same difference when using rotational hard drives. There's certainly no bottleneck slower than the rotational hard drive itself, so why is there a speed difference between the two computers? I assume there's something in the Mini's chipset or the CPU itself that lets it handle data transfer more efficiently.

 

[mmomega]

Interesting though.
I'd like to test this myself across a few different Macs of various years.

 

[ColdCase]

Latency and HD cache affects USB protocol in unexpected ways. So a rotational drive could performs differently from one host USB implementation to another. Its more than the number of bits than can be pushed through the pipe as the drive may write and acknowledge which can have some variations.