Terrible NAS transmition speed. 1/10 of what it should be

Discussion in 'Networking Issues' started by kwanbis, Feb 20, 2008.

  1. kwanbis

    kwanbis LI Guru Member

    Hi everybody, first post here.

    I have a a WRT54GL 1.1 flashed with DDWRT v23 SP2.

    I also have a 1 Terabyte NAS drive, connected to the WRT54GL, directly through wired ethernet.

    Internet on my 2.5 mbit connection works perfect: i get 200 kbit/s or more.

    But if I transfer files from my NAS to my PC, or viceversa, i get much worse performance

    I find it very weird, as my WRT54GL+DDWRT is supposedly a very high performance router.

    I tried connecting by wireless, and by ethernet, and while by ethernet is better, it is not acceptable.

    For example, i can not see real time an Xvid from the NAS, i have to download to my HD.

    Copying a 700MB file from my laptop to my NAS, using my 54mbit wireless connection, takes 10 minutes.

    If i'm connecting at 54mbit, that means 6.75 mbytes per second, even if we round it to 6, this connection should transfer 360 mbytes per minute, so it should be done in 2 minutes.

    In the case of wired ethernet, it should be transferred in a minute.

    I was told that the NAS sends a lot of UDP packets and that that is the problem, but i still don't buy it.

    Any ideas? Thanks.
  2. mstombs

    mstombs Network Guru Member


    54Mb/s Wireless G is half-duplex - the bandwidth is shared between all clients, and there is a lot of overhead/ security etc which slows down the maximum throughput on a one-to one link to closer to 20Mb/s (Maybe 27Mb/s if you have Speedbooster '125 mode' and a very strong signal - lots of marketing hype in selling wireless!).

    Full duplex 100Mb/s wired Ethernet on the other hand can achieve much closer to theoretical throughput, but even then a router such as WRT54GL may slow the connection down to 35Mb/s from LAN to WAN. LAN to LAN is handled by the switch so should be faster.

    Have a look at reviews on Toms Networking guides for throughput studies, and reviews of the NAS200 for pointing out the NAS transfer rate may be limited by the NAS CPU to disk transfer rate.
  3. kwanbis

    kwanbis LI Guru Member

    Thanks for your response.

    I was using the wireless connection only by myself, and at most one more computer that could have been just browsing.

    Anyway, even at the 20Mb/s speed, it should take no more than 5 minutes, to trasnfer 750 MB.

    This is taking DOUBLE that amount.
  4. mstombs

    mstombs Network Guru Member

    Well things have moved on - when I first got a WRT54GSv1.1 some years ago it couldn't transfer a CD image without breaking the connection! When fixed I recall I could get a bit over 20Mb/s from wired computer to wireless computer but then it was halved again if going from wireless to wireless - not a patch on hard-wired Cat 5! A further trouble with any testing with wireless is the results are not that repeatable - depending on wireless interference I guess.

    So I think you should be able to improve things a bit - try tweaking the TCP/IP settings especially RWIN for example - but don't expect miracles!
  5. kwanbis

    kwanbis LI Guru Member

    So you mean that 54mbit wireless is a lie?

    How comes it takes the same time to download a 700 MB file from internet to my HD, as from my NAS to my HD?

    I really don't get it.
  6. mstombs

    mstombs Network Guru Member

    I'm sure there is something in wireless G that sends data at 54Mbs, but it only does it for a fraction of the time in any one direction - see wireless throughput numbers here for example


    Have a look here for measured NAS transfer rates (in MBytes/second)


    You don't say what NAS you have - you should get at least 2MBytes per second (20Mbits/second), so should still be noticeably faster than internet?
  7. kwanbis

    kwanbis LI Guru Member

    I have a gforce megadisk nas (link).

    And no, i'm not getting better performance as downloading from the internets ;)
  8. Toxic

    Toxic Administrator Staff Member

    that is theoretical maximum you are guessing on, distance and interference will lower the wifi speeds.

    can you confirm if you are having the same speed issues if the laptop uses a wired connection to the router?

    are you haev mixed mode or set to G only for the wireless connection?
  9. mstombs

    mstombs Network Guru Member

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