Slow Wifi on 1 device..other devices working fine

[Sandyuser]

I recently bought Netgear N300 Wifi cable modem router (C3000-100NAS) and i see that the Wifi speed on one of my devices is very slow (<3 Mbps-Lenovo desktop). On all the other devices I am getting approx 20 Mbps. I tried putting all my devices in the same place to test the signal.Still Lenovo desktop gives very slow speed.

I tried changing the wireless channel but that didnt help.

I also tried updating the wireless drivers and that didnt help either.

Is there some other settings that need to be changed.

Any help on this would be highly appreciated

[Babylon5]

Can you tell us what model of WiFi adaptor the Lenovo is fitted with please (from the Device Manager screen)? Also the device fitted to the other computers if you don’t mind.

[Sandyuser]

Lenovo has "1X1 11 b/g/n Wireless LAN PCI Express Half Mini Card Adapter" by Realtek.

The other device has "802.11n Wireless Lan Adapter" by Ralink

[Sandyuser]

The problem isn't solved. probably will have to replace the netgear router with a diff one