Here is my setup:
Samsung ATIV 9 Plus ultrabook computer (model NP940X3G K04US) running Windows 8.1 with all available Microsoft updates.
Computer has Intel 7260NGW AN wireless network card.
Comcast Arris TG862 cable modem/router - outputs 802.11n 2.4 Ghz Wi-Fi (not dual band).
Cradlepoint MBR1000 Router (with version 2.0 firmware) - outputs 802.11n 2.4 Ghz Wi-Fi (not dual band). Connected to the Comcast router via an Ethernet cable.
My Comcast internet connection gives me 120 Mbps download speeds when connected to a computer using an Ethernet cable.
Using the Samsung laptop connected via Wi-Fi to the Comcast router I get download speeds of about 23 Mbps using www.speedtest.net.
Using the Samsung laptop connected via Wi-Fi to the Cradlepoint router I get download speeds of about 70 Mbps using www.speedtest.net.
Using a Dell laptop connected via Wi-Fi to the Comcast router I get download speeds of about 80 Mbps using www.speedtest.net.
The laptops are about 3' from both of the routers.
The Samsung laptop is using Intel version 220.127.116.11 drivers for the 7260NGW AN network adapter (latest available that I can find)
The advanced settings for the 7260 are as follows:
802.11n Channel Width for 2.4 Ghz - Auto
802.11n Channel Width for 5.2 Ghz - Auto
Ad Hoc Channel 802.11 b/g - 1
Ad Hoc QoS Mode - Wmm Disabled
ARP offload for WoWLAN - Disabled
Bluetooth(R) AMP - Enabled
Fat Channel Intolerant - Disabled
GTK rekeying for WoWLAN - Enabled
HT Mode - HT Mode
Mixed Mode Protection - CTS-to-self Enabled
NS offload for WoWLAN - Enabled
Packet Coalescing - Enabled
Preferred Band - 2. Prefer 2.4 Ghz band
Roaming Aggressiveness - 5. Highest
Sleep on WoWLAN Disconnect - Disabled
Transmit Power - 5. Highest
U-APSD support - Disabled
Wake on Magic Packet - Disabled
Wake on Pattern Match - Disabled
Wireless Mode - 6. 802.11 a/b/g
I have tried various versions of the Intel drivers going back to the 15 series and still get the same results. I have also tried the Microsoft drivers that are supplied with Windows 8.1 - still no improvement. I have also tried a variety of advanced settings for the 7260, still with no change in speeds when connected to the Comcast router.
Can anyone from Intel help me figure out why I am getting significantly slower download speeds when connected to my Comcast router as compared to my Cradlepoint router?