Very slow USB transfer speeds

[Uoppi]

I'm getting awful transfer speeds with a 2 TB USB drive attached as a NAS.

FTP or Samba, the speed maxes out at 1 MB/s. Same thing wired or wireless, using Windows 7 or 8. The drive is formatted in EXT3 and integrity checked with Gparted. No luck switching between firmwares (including the latest build by Merlin). Gone through the usual mtd-erase -d nvram etc. stuff meticulously each time. System log reports no disk errors upon mounting, no IO/dead device errors either.

With RT-N56U and the same drive I was able to sustain transfer speeds of over 10MB/s. Now I'm getting less than one tenth of that! Sometimes the speed is up there for a few seconds at the start until it quickly drops. The connection is maintained but the speed never jumps back to normal. Qos is disabled btw, fiddling with that made no difference.

Any suggestions are appreciated, I've tried pretty much everything I can think of. It took me months (!) to get the RT-N56U finally working (the official Asuswrt fw seemed to do the trick). Now I'm kind of back to square one and out of ideas.

 

[RMerlin]

Make sure all your network cables are rated for Cat5e or Cat6 - the gigabit ports will have stability issues if you use older Cat5 cables.

This wouldn't have any impact on wireless, but start by troubleshooting a wired connection to rule out any wireless-specific issues.

Might also be worth trying another USB cable, just to be safe.

 

[Uoppi]

Here's some of the things I've found out:

- All cables are working (Ethernet cable is Cat6)
- Anti-virus or firewall interference is ruled out
- Disabling Qos or IPV6 from Windows doesn't make a difference
- Tried both USB ports
- Tried disabling DLNA server, UPnP, made sure miniDLNA scan is idle etc.
- Problem is present with both ftp and Samba
- Problem is present with both EXT3 and NTFS (tried two different drives)
- Problem is present both via wireless and wired (tried two PCs)
- Problem is present with both Win 7 and Win 8 (tried two PCs)
- File transfer speed via LAN is excellent between the desktop and laptop
- WAN to LAN speed is excellent in both wired and wireless
- Reverting back to previous firmwares makes no difference

Conclusion: there's definitely something funny with the router's USB ports/drivers etc.

I seem to be the only one with this problem so I'm wondering if I received a flaky unit. Like I wrote, my RT-N56U with the Asuswrt firmware and identical setup worked faultlessly literally minutes before switching to the AC66U.

Edit: It's so weird to see transfers start at "full throttle" and after two or three seconds the router drops it down to ~1Mb/s and keeps it there. It's almost like the router is setting a limit there because other than the speed the connection seems stable.

 

[RMerlin]

Are you using Jumbo frame at any point on your network? If so make sure you disable it (or set frame size to 1500 bytes) - this could be another reason for such throughput issues.

Only one more test I'd try is to see if the issue occur if you only have the router and one computer connected - unplug both the WAN and the other network devices to rule out any possible issue caused by one of these.

Beyond that... I would try contacting Asus. It's possible you got a defective router.

 

[Uoppi]

Unplugged all other network cables (including WAN), rebooted and tried file transfer: stable connection but only ~975KB/s as expected. Tried wired connection with two different PC's with two different cables and two different operation systems.

"Enable Jumbo Frame" is at the default "No" setting in the router.

I'm clueless as to why only yesterday the transfer speed was 10MB/s+ for maybe ten seconds before dropping but now it drops instantly or near-instantly.

What's more, I have a vague recollection that the very first USB test transfer(s) I did with the router, the transfer speed was OK. Not 100% sure if I remember right though - it may have been when the RT-N56U was still in use.

All in all, it feels as if the USB ports have quickly "degraded". And I only bought this router on Saturday!

 

[Uoppi]

Update: I exchanged the router for a new one and the transfer speeds are now up there where they should be.