Thanks for getting back to me.
• Currently using out of the box cables that came with the QNAP. Cable between Mac and Hub is also a new one.
• Checked all the settings you suggested both sides, all as you specify.
• No error packets.
• Back to back connection seems to produce no discernible difference.
• When copying the CPU is maxed out pretty much throughout copy. Top processes are 'afpd' which is averaging between 30% and 75%, currently idling around 35% but with spikes; 'md0_raid5' which seems to take about 10% with spikes of 20%.
• Checking all the various management pages and logs doesn't seem to highlight any problems.
A couple of points of interest, maybe.
Overnight it hung trying to copy a load of folders from the old music directory to the new one (just to be clear old one is on a STORA, but I have tested file transfer both from an external HD connected by Firewire 800 and from internal Mac HD with same speed results). To be precise, I had been copying one folder and going fine so decided to see what happened if added a whole other stack. At that point it appears to have hung at the 'preparing to copy point', creating all the folders but transferring nothing, while the transfer that had been motoring along then hung also. So I was left with a music folder full of empty folders. When I tried to delete these from Finder going was exceptionally slow. However, when I deleted them using the Web File Manager had a totally different experience and they couldn't have gone any faster.
It appears to be slower the more folders I attempt to move at once (in a single copy, rather than starting a second one before first is complete, which is what caused everything to hang overnight). Currently moving a stack of about 60 folders (all of which will have at least one sub-directory as you will no doubt have guessed given iTunes file structure). Average bandwidth use is around 6 mbps according to the Resource Monitor. It seemed marginally faster, averaging perhaps 9 mbps for a single folder with just one sub-folder.
I plan to try uploading an album of songs via the web file manager when it has finished current transfer (claiming it will take 35mins for about 17gbs of data) and see whether i get different results in resource monitor. Not sure what that will tell me, or you, but there does seem to be a significant difference between this and finder when I delete files, so I wonder whether the same is true of writing. Will update when I have a result.
Anyway, hopefully this helps you to understand whats going on here. Thanks for the help thus far.
My experiment with the Web File Manager produces same results and speed for upload. In processes 'utilRequest.cgi' is the biggie with usage spiking to 70%. CPU graph a bit more spiky as opposed to almost permanently maxed out, but still maxing out regularly.
In other news, when I transfer a small amount of files without sub-directories things seem to a lot faster, i.e. peaks of 12 mbps instead of 9mbps.