Question regarding USB 3.0 External HDDs

[FlipperBizkut]

I have two different 3TB USB 3.0 external drives (both Seagate 7200 RPM drives in the shells). I am trying to copy some data from one to the other (brand new). I have them both plugged into the USB 3.0 ports of my desktop, but I am getting horrible speeds.

If I copy some data from the first drive to one of my internal drives, I am getting around 135MB/s - which I am plenty happy with. If I transfer that same data to the new second external, I am getting around 85MB/s writes - which I am also plenty happy with.

These two transfers (to and from the internal drive) occurred while both externals were still plugged in. I say that because no wires were moved/changed/jiggled or anything, and nothing else changed with how the system was set up. But, when trying to transfer from one external to the other (skipping the internal drive "middle man"), I would get speeds of around 3MB/s or so.

Transfers were attempted using FreeFileSync and also using simple file transfers from within Windows 7.

I started moving some of this data yesterday, and was not experiencing this dilemma at first. It just started for no reason that I can figure out. Of course I have tried system restarts, changing plugs, cables, etc. I also connected one drive to the front ports (connected by the blue mobo header), and the other to the rear ports, but that didn't do anything either.

Any ideas?

 

[drescherjm]

Turn on write caching on the device in device manager. Most likely windows has the write cache disabled on the drive. I believe one of the settings that needs to be disabled is optimize for safe removal.

 

[FlipperBizkut]

Thanks for the idea. Write caching was already enabled though. I did check the box to eliminate Windows from flushing the buffer since the drive has its own power supply, and once I checked that box, the Asus AI Suite crashed.

I thought that was weird, but then realized that part of that AI Suite was the USB 3.0 Turbo thing. Wondering if that may have something to do with my problem, I unchecked the box I had just checked to get the drives back to the way they were before, and I left the AI Suite off.

Problem solved! I'm now getting constant writes in the 120-150MB/s range going straight from one external to the other over USB 3.0. Excellent!

Thanks so much.