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The Graveyard - Products No Longer Supported => Routers / COVR => DIR-655 => Topic started by: Still Busy on January 01, 2009, 10:13:18 PM

Title: DIR 655 and DSM 750 Poor 11.n Performance
Post by: Still Busy on January 01, 2009, 10:13:18 PM

I have a DLink DIR 655 router (firmware 1.21) set to 11.n only mode and 40 MHz with Security Mode-None (all advanced setting as per factory defaults).

Connected to the router through a 100 MB ethernet link is my computer.
The only wireless client is a Dlink DSM-750 (firmware 1.02).  (router reports 300 MB connection and 100% signal)

When I play 720P movies over the wireless 300 MB link, during quickly changing screens the 750 often stutters, losses sync and losses sound.

The same scenes play perfectly when connected using a 100 MB ethernet NIC on the same computer.

The network utilization (reported by task manager on my computer) of the ethernet link peaks at ~15%.  The wireless peaks at ~10%.

So my question is why does the 100 Mbyte ethernet link outperform the 300 Mbyte wireless link?
Is their extra overhead within the DSM-750 for wireless?
Is this normal behaviour of wireless vs wired?
Are their any advanced settings which would allow the 300MB wireless link to work better?
Potential firmware improvements?

I bought this router specifically to drive the Dsm 750 wirelessly.

Thanks

Title: Re: DIR 655 and DSM 750 Poor 11.n Performance
Post by: EddieZ on January 02, 2009, 02:06:09 AM

Because
1.the 300 Mbit is only a theoretical speed. You will get 80 to 120 Mbit max from it.
2. wireless in general is -by nature- known for being vulnerable for more lag and fluctuating connection quality whereas wired ethernet is rocksolid (when right cable quality is used; CAT 5e and +) since wires are not affected by interference from neighbouring AP's, DECT phones, static, concrete walls/steel in walls,  etc.
3. 720P movies can have different bitrates. The higher the bitrate, the more bandwidth is needed (MB/s; do not mix up Mbps with MB/s, Google for online calculators that convert Mbps to MB/s)).

Title: Re: DIR 655 and DSM 750 Poor 11.n Performance
Post by: funchords on January 03, 2009, 04:20:48 PM

Set the DIR-655 completely to factory defaults and repeat your test using the same rapidly-scene-changing portion.

If this helps, it's because you were locked into a bitrate that was too high for your local conditions and you configuration disabled the ability for the DIR-655 to float to the most effective bitrate.   

Is your home located in an urban, suburban, or rural area?

Title: Re: DIR 655 and DSM 750 Poor 11.n Performance
Post by: EddieZ on January 04, 2009, 03:27:58 AM

Quote from: funchords on January 03, 2009, 04:20:48 PM

Set the DIR-655 completely to factory defaults and repeat your test using the same rapidly-scene-changing portion.

Caution! Depending on your configuration this can cause disconnection, so have a backup of your config on a wired PC ready.