My book Studio II 6tb RAID 1 write speed < 5mbs


Have spent most today educating myself via google in attempt to understand then resolve this issue. No luck so far…


VERY slow write speed to mybook Studio II 6tb. 

Eg. data writing <5gb of photos took > 2 hours 

Blackmagic speed test - reports write failure/ or <4Mbps

So far I have:

Power cycled Ext HDD

Power cycled iMac

Tried USB connection instead

Run WD Raid Manager - both disks reported as ‘Good’

Dismounted and mounted to a late 2009 Macbook, on Snow Leopard, via USB. Same issue.

Duplicated files that exist on the drives. 3.5Gb file duplication required an 1hour. So same issue.

This, inparticular, makes me think it is not the connection but something not correct with the drive itself

Reivewed firmware and drivers on support site, and whilst there is a +TURBO option for this drive, the current performance belies a significant problem that I wish to fix before introducing further variables. 

This idrive wsa previously working fine, however, (disappointingly) I am unable to pinpoint the exact start date and subsequent change that may be causing it.

Any ideas welcome…



A further point, read speeds are fine. 10Gb of data moved FROM myBook to my Laptop, via USB 2 is about 5 minutes.

Many things can afftct transfer speed, The read/write speed of the actual computer drive, antivirus and antimalware software, drivers in the whole USB or firewire chain. If there are updated drivers from the hardware manufacturer for of the devices involved update them. I don’t know much about Macs but in Windows you would want to check out the BIOS for updates.