slow USB hard drive transfer rate

[east river]

Operation system: Windows 7
Hard Drive: WD passport 1TB, NTFS file system
Router: TP-LINK TL-WDR3600 N600
Router Firmware: Gargoyle 1.59
Transfer Speed: 2MB/s

the writing speed over wifi is only 2MB/s, what's wrong with it?
I only have limited knowledge about the firmware setup, e.g. to setup via the web interface.
The router is working fine, Wifi internet speed (through Charter cable) can reach 30Mbps download, 4Mbps upload.

Any suggestion on increasing the transfer speed? Thanks in advance!

[Slacker]

That's about what I get on NTFS, too. There's some info on
http://www.gargoyle-router.com/phpbb/vi ... 1109#p5292 , but not much you can do, if you want to keep NTFS.