Ridiculous SMB file transfer speed - 10 hours for 4gb

[liquidwitch]

Hi Guys, Really keen to get amongst this community - love my pi.

So I've got a weird one. Extremely slow transfer speed over wifi, saying it's going to take 10 hours to transfer a 4gb file.

- running XBian 1.0 Beta2
- Wifi sync on computer is at 144 Mbit/s
- Transferring from OSX 10.9
- Drive is 4TB EXT4 formatted - powered
- I've turned off sync in usbmount.conf
- USB transfer speed is ok - 524288000 bytes (524 MB) copied, 19.4418 s, 27.0 MB/s
- Pi is using wifi dongle - this isn't powered
- Pi is using a 5v 1a iPhone changer

So yeah, I know I could use ethernet for both, but it's much for convenient to get wifi working at a reasonable rate.

Another, possibly related point - When downloading with transmission the Pi is practically unusable, SSH takes about 5 seconds to respond and the network share is impossible to navigate.

Any help will be really appreciated, cheers.