Slow speeds - Broadcom BCM4313

experience slow download speeds (5 to 17mbps) w/old lenovo 20150 ideapad (i5-3230M chipset)
wireless card: Broadcom BCM4313 802.11b/g LP-PHY
router: asus rt-nt56u w/2.4 & 5GHz bandwithd
2.4Ghz configured
Mode: Auto with b/g protection enabled
channel: 20/40 Mhz
Control & Extension Channels: Auto
WPA2 with AES
Group Key Rotation: 3600

on a wireless adapter I tried to change IBSS Mode from 802.11b only to 802.11b/g/n Auto to 54g - almost no change in download speeds. also changed Bandwidth Capability from 11b/g 20 Mhz to 11b/g 20/40Mhz

Not sure what else can be done to increase speed.
Tested wireless speed connection on ipad air 2 in the same room where the laptop is located. The download speed on ipad is about 4 to 5 times faster

 

What is the connection speed as reported by Windows?
I don't mean the actual transfer speed but what Windows reports as theoretical connection speed.

 

Windows's Signal Quality varies. Most of the time it shows 39 Mbps, but when I rechecked it now, it jumped from 19.5 to 52 and back 26 Mbps

 

This seems to indicate that the connection is 802.11g not 802.11n even though the card is capable of the latter.
With 802.11g connection you can't hope for more than 20mbps in ideal signal conditions, which would be roughly what you can get (up to 17mbps).

Check the advanced driver settings again - ignore IBSS settings - these apply only to ad hoc connections.
Disable any power-saving in driver advanced settings, make sure WMM is enabled (if such setting is available) and make sure your driver is up to date.

 

@Samal You might check whitelisted Wifi cards compatible with Lenovo ideapad

 

i rolled back adapter's driver ver to 6.30.223.143. Changed power settings as well. Rebooted. No effect. The day after 47mbps

 

Thank you all!