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I have an HP Elitebook 8470w connected to an Inateck USB 3.0 to SATA Docking Station with a Crucial 64gb M4 SSD plugged into it.
So why am I seeing un-cached sequential read speeds of only ~30MB/s?
Edit - I discovered I had the drive connected to a USB 2.0 port on the laptop. When connected to the USB 3.0 port I'm now seeing closer to ~170MB/s which is still a long way from the ~410MB/s I was expecting.
Jon Cage
Posted 2014-02-17T09:40:22.600
Reputation: 2 289
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A response from the dock manufacturer (Inateck) clears a few things up:
You use the natively embedded generic Intel host controller, comprising a simulated PCI-E v1.0 interface, which it does not feature actually. But still, the PCI-E bridge is now determined to be the bottleneck, which means with the simulated revision version, the highest bandwidth your interface can reach should be 250 MB/s. Therefore, the 170 odd MB/s stays well within realistic parameters.
Still, I'm sorry about this situation, as it can't be helped directly, safe for a possible firmware update and BIOS flash, apart from the reconfiguration of the SSD formatting, converting to 4k sector alignment, or even resetting all sectors to "0" on it. That at least should speed things up a tad.
Jon Cage
Posted 2014-02-17T09:40:22.600
Reputation: 2 289
Some information here suggests higher transfer speeds should be possible: http://h30434.www3.hp.com/t5/Notebook-Hardware/EliteBook-8740w-USB-3-0-poor-performance/td-p/1488037
– Jon Cage – 2014-02-18T14:01:11.210...but despite various driver updates I'm still limited at around the 170MB/s mark. – Jon Cage – 2014-02-18T15:53:24.667
Stupid Question(tm): Are you sure it is plugged into an USB3 port and those ports have the USB3 driver loaded? Also are you sure to read with 4KB blocksize aligned? For example the partition must not start at Sector 63, else you have unaligned reads. – Tino – 2014-02-17T10:17:11.290
I had assumed so, but checking the connections with http://www.uwe-sieber.de/usbtreeview_e.html#download it would seem the USB ports on the right of the laptop are only USB 2.0! On the USB 3.0 port I'm getting ~170MB/s.
– Jon Cage – 2014-02-17T11:52:33.497How can I check on partition location and is NTFS a problem performance-wise? – Jon Cage – 2014-02-17T11:55:33.543
Our real-world benchmark (simulating some software we're trying to optimise for read speed) is reading 1051 bytes per read which presumably could slow things down as it's not a multiple of 4k? Even on a file cached by Windows in RAM we only get up to ~220MB/s.. – Jon Cage – 2014-02-17T12:07:59.877