[Rocky14]

I followed the initial flash guide in the wiki first
http://dd-wrt.com/wiki/index.php/Linksys_WRT320N_v1.0

Then used the most recent build from ftp://ftp.dd-wrt.com/others/eko/V24-K26/svn15508/
picked the build - dd-wrt.v24-15508_NEWD-2_K2.6_big.bin

Referred to http://www.dd-wrt.com/wiki/index.php/Wireless-N_Configuration

Set Channel = 11. I also did a site survey to verify Neighbor's Wireless Networks don't have this channel.
Set Security as WPA2 Personal with AES encryption
Lowered TX Power from 71 to 40mW

I used speedtest.net to test the wireless speed. Consistently on wired connection the download speed is 25mbps. On wireless it is 5 to 7mbps. About 80% loss in throughput.

Exact router model listed on the bottom sticker: WRT320N
Exact firmware build: DD-WRT v24-sp2 (10/26/10) big - build 15508M NEWD-2 K2.6 Eko
Exact client adapter model: Intel(R) WiFi Link 5100 AGN #2
Exact client adapter driver version: 13.2.0.30
Which spectrum 2.4GHz or 5GHz: 2.4GHz
Which channel: 11 - 2.462GHz
Channel width: 20MHz
Encryption settings: WPA2 Personal AES
Distance between the client and AP: ~ 3 Meters
Signal/Noise/SNR of the connection listed in the router's wireless status: Excellent
Type of materials between client and AP (wood, brick, metal, sheet-rock): Nothing

[phuzi0n]

Test your throughput to a wired device on your LAN if you can. Try the other non overlapping channels (1 and 6) in case something is interfering.

[Rocky14]

Thanks phuzi0n for your swift response. I tested the LAN connection speed between my PC and Xbox using the Media Center. Speed works really well between wired Ethernet connections but not on wireless. I understand that there will always be a loss on wireless but my problem is that it's horridly low. I tested with channels 1 and 6 and the results were same.

Would you please advice if there are any additional settings I can play around with? Also can you recommend any tests that will help me understand the bottleneck? Thanks in advance for your response.

On phuzi0n's signature I read that you are looking for bricks and spare routers for testing/tutorials. I have my old working router Netgear WGR614v5 that I can send if you find it useful.

[phuzi0n]

[Rocky14]

I converted WRT320N to E2000 following the instructions below.
http://www.dd-wrt.com/phpBB2/viewtopic.php?t=76924&highlight=convert+320n+e2000

I see significant improvement on the wirless speed after that. Attached the Bandwidth Monitor Status as well.

Thanks for your prompt responses.