Windows 7: Issue with config on one pc on wireless home network

Hi,

For the last couple of weeks, i've had rubbish speed on my pc when connected to wireless. Used to get around 6Mbps bandwidth but this has decreased to around 2Mbs.

I have 2 other machines (i have not tampered with :/) on the same network which perform fine (around 6Mbps).

I tried several 'Speedguide' tweaks (including Nagle algorythm tweak) but get varying speeds and 'rubberbanding' when playing games online (BF3) and huge lag spikes (from around 40ms up to 1000+).

Specs:
Win 7 Home Premium, Intel i7 2600k @ 3.4gh
Netgear DG834G v4
BIOS, router firmware and all drivers are up to date.

Please find below my analyser results:

« SpeedGuide.net TCP Analyzer Results »
Tested on: 2012.12.21 05:26
IP address: 2.99.xxx.xxx
Client OS/browser: Windows 7 (Chrome 23.0.1271.95)



TCP options string: 020405b401010402
MSS: 1460
MTU: 1500
TCP Window: 64240 (multiple of MSS)
RWIN Scaling: 0 bits
Unscaled RWIN : 64240
Recommended RWINs: 64240, 128480, 256960, 513920, 1027840
BDP limit (200ms): 2570kbps (321KBytes/s)
BDP limit (500ms): 1028kbps (128KBytes/s)
MTU Discovery: ON
TTL: 108
Timestamps: OFF
SACKs: ON
IP ToS: 00000000 (0)

I hope someone can suggest something.

Cheers!

What is the make and model of your router?

What is the signal strength on these machines?

There are settings in your routers set up page that can have a dramatic effect on wireless performance, 6Mbps is terrible.

If you can post a screen shot of the Xirrus WiFi inspector it will help greatly.
Wi-Fi Inspector | Xirrus

Hi, it's a netgear dg834g v4. My building can only get adsl so it's unfortunately 8mbps max.
Other machines have full signal, mine not so (addon npw 220 wireless adapter I tthink).
I've left for hols now so won't be able to post xirrius results for a couple of weeks.
Thanks and happy xmas