Default Weak WIFI speeds ~ 10-20 Mbit - Suggestions?

Hey!

Has anyone else had problems with their wifi connection?

My D802 rarely goes over 1,5 MB/s on SMB and rarely over 2,5 MB/s on FTP.

(ES file explorer, tried both 2.4 / 5 GHz, tried three routers atheros/broadcom AC + Linksys G latest firmwares)

Same wifi setup results in transfer speeds of 15-25 MB/s on two laptops with the current Netgear R7000 ac-router I'm on now.

Link speed in the G2 is shown as 433 Mbps. Running latest CM11 nightly 0224 rom but tried the original LG 4.2.2 with same result.

Is there a modem update or better app that can improve the transfer speeds? How about the official 4.4.2 update, does it come with any speed improvements?

I appreciate any suggestions you may have. /s