Asus PCE N53 is slower than iPhone and RT N10U used as bridge

[kosmik]

I tried to change my current wireless setup and run into problems, I would really appreciate any help here.

My setup was the following:
* "Router" Asus RT N10U connected to provider (IPoe) and serving as wifi access point for everything else in my apartments. I'm using 802.11 G/N mixed mode because one of clients is Xbox 360 which for some reasons connects only as "G". I also using 20MHz because on 40 network performance is very shaky and slow.
* I have another "Bridge" Asus RT N10U which runs DD-wrt, connecting wirelessly to "Router" and serving as a wireless bridge for my HTPC which is the heaviest bandwidth user (sometimes torrents, sometimes youtube)
* I also have a bunch of other wireless devices (anoher PC, macbook, 2 iphones, ipad and XBox)
* I have cable modem (connected to router WAN port) which gives me 40Mbps incoming/5Mbps outgoing traffic if I connect my laptop to one of LAN ports of my "router". I'm using "speedtest" which is hosted by my network provider. My max allowed downlink is 50Mbps btw.

Why I wanted to change:
* I don't want another box in main room where I have HTPC (just aesthetics )
* I get only 30Mbps downlink on HTPC, I want to have approximately the same speed as on LAN port of router

My idea was to get rid of "bridge" N10U and put in dual-band wifi card into my HTPC directly, hoping it will not make things worse in 2.4GHz and will allow me to experiment with dual-band routers later.

So I bought Asus PCE N53 card, plugged it into my HTPC (Windows 8.1) and after finally making it work found that instead of more-or-less stable 30Mbps I get something between 12 and 28, typically around 20Mbps.

I've been trying to re-position router and HTPC slightly (and HTPC has a slim aluminium case, but antennas are not really covered by it) - no luck. So I did two experiments:
1. I connected "bridge" again and put its antenna side-by-side with network card's one.
2. I placed my iPhone running Speetest behind HTPC case, so there was no even direct like of sight between it and my primary router.

In both cases speedtest shown 30Mbps very stable.

So to me it doesn't look like something related to device positioning. My only guess now is that card is just faulty, but maybe I'm doing something completely wrong or there is a clear disadvantage comparing to separate "bridge" I've been using? Or maybe there is some kind of incompatibility between card/router models?

Wireless network
* 802.11 G/N mixed mode
* 20Mhz
* WPA2 Personal / AES
* Channel 6 (the only channel I get stable link)
* HTPC/Windows has 4-5 bars on this wifi connection. It shows 58-76Mbps link in adapter info.
* DD-wrt on my primary router shows 100% signal quality for HTPC

I also do have latest drivers for PCI card from Asus website.

 

[L&LD]

Try setting up a new ssid with the new adaptor. It may be all it needs to connect faster.

 

[kosmik]

I tried this, but I don't see any persistent visible improvement.

Actually, I might have improved throughput slightly (but maybe it was just very late so there were less devices/interference) by noticing that on my Macbook (running Windows 7) which performs much better over wifi the tcp config is slightly different:

LAPTOP
----------------------------------------------
Receive-Side Scaling State : enabled
Chimney Offload State : automatic
NetDMA State : enabled
Direct Cache Acess (DCA) : disabled
Receive Window Auto-Tuning Level : normal
Add-On Congestion Control Provider : none
ECN Capability : disabled
RFC 1323 Timestamps : disabled
** The above autotuninglevel setting is the result of Windows Scaling heuristics
overriding any local/policy configuration on at least one profile.


HTPC
----------------------------------------------
Receive-Side Scaling State : enabled
Chimney Offload State : disabled
NetDMA State : disabled
Direct Cache Access (DCA) : disabled
Receive Window Auto-Tuning Level : normal
Add-On Congestion Control Provider : none
ECN Capability : disabled
RFC 1323 Timestamps : disabled
Initial RTO : 3000
Receive Segment Coalescing State : disabled
Non Sack Rtt Resiliency : disabled
Max SYN Retransmissions : 2

What I did is that I enabled "Chimney Offload State", "ECN Capability" and "Receive Segment Coalescing State".

After that the throughput become between 20-30Mbps, with around 28Mpbs most of the time.

Maybe the reason is really in some configuration which increase overhead? Like sending small packets instead of aggregating them?

BTW, I don't see any transmission errors neither on router side nor in Windows Performance Monitor...

 

[fsatsil]

20-30Mbps seems pretty good for an RT-N10U running in G/N mixed mode at 20mhz with a bridge. What kind of speeds are you expecting?

 

[kosmik]

I was expecting to get at least the same speed as I get with wireless bridge and which I also get with iPhone: 30Mbps stable. Now I almost get it after tweaking TCP stack settings, but with bridge it seems more stable and _slightly_ higher. However I didn't have time to do more testing after I did settings change.

 

[kosmik]

After more testing I can say that it didn't really helped. Connecting via wireless bridge is way more robust and higher bandwidth.

 

[kosmik]

Finally I took new AirPort Extreme from office and tested with it instead of my primary router.

In 2.4GHz nothing has changed. In 5GHz I've got 40-50Mbps. So I'm just going to buy something dual-band and move my HTPC to 5GHz.