I have a very similar problem with this post:

Ubuntu 14.04 Slow and unstable wifi connection

But I could not comment there and that's why I'm asking a new question.

I have a notebook with dual boot windows 8 / ubuntu 14. My wifi internet works just fine in windows but it is very slow and unstable in ubuntu: the conection drops every 5 minutes or so.

I've tried a lot of different solutions (including upgrading kernel to 3.17.1). I've also tried the solution proposed by Chili555 in the link above (but changing "rtl8188ee" for "rtl8723be") and nothing seems to work.

Here are some informations about my notebook

 $sudo lshw -C network

 *-network               

       descrição: Ethernet interface

       produto: RTL8101E/RTL8102E PCI Express Fast Ethernet controller

       fabricante: Realtek Semiconductor Co., Ltd.

       ID físico: 0

       informações do barramento: pci@0000:08:00.0

       nome lógico: eth0

       versão: 07

       serial: 34:64:a9:75:ff:7a

       tamanho: 10Mbit/s

       capacidade: 100Mbit/s

       largura: 64 bits

       clock: 33MHz

       capacidades: pm msi pciexpress msix vpd bus_master cap_list ethernet physical tp mii 10bt 10bt-fd 100bt 100bt-fd autonegotiation

       configuração: autonegotiation=on broadcast=yes driver=r8169 driverversion=2.3LK-NAPI duplex=half firmware=rtl8106e-1_0.0.1 06/29/12 latency=0 link=no multicast=yes port=MII speed=10Mbit/s

       recursos: irq:41 porta de E/S:5000(tamanho=256) memória:b5600000-b5600fff memória:b5400000-b5403fff



  *-network

       descrição: Interface sem fio

       produto: RTL8723BE PCIe Wireless Network Adapter

       fabricante: Realtek Semiconductor Co., Ltd.

       ID físico: 0

       informações do barramento: pci@0000:0a:00.0

       nome lógico: wlan0

       versão: 00

       serial: 10:08:b1:3b:3d:11

       largura: 64 bits

       clock: 33MHz

       capacidades: pm msi pciexpress bus_master cap_list ethernet physical wireless

       configuração: broadcast=yes driver=rtl8723be driverversion=3.17.1-031701-generic firmware=N/A ip=10.110.80.14 latency=0 link=yes multicast=yes wireless=IEEE 802.11bgn

       recursos: irq:46 porta de E/S:3000(tamanho=256) memória:b5500000-b5503fff





$ifconfig -a



eth0      Link encap:Ethernet  Endereço de HW 34:64:a9:75:ff:7a  

          UP BROADCAST MULTICAST  MTU:1500  Métrica:1

          pacotes RX:0 erros:0 descartados:0 excesso:0 quadro:0

          Pacotes TX:0 erros:0 descartados:0 excesso:0 portadora:0

          colisões:0 txqueuelen:1000 

          RX bytes:0 (0.0 B) TX bytes:0 (0.0 B)



lo        Link encap:Loopback Local  

          inet end.: 127.0.0.1  Masc:255.0.0.0

          endereço inet6: ::1/128 Escopo:Máquina

          UP LOOPBACK RUNNING  MTU:65536  Métrica:1

          pacotes RX:156 erros:0 descartados:0 excesso:0 quadro:0

          Pacotes TX:156 erros:0 descartados:0 excesso:0 portadora:0

          colisões:0 txqueuelen:0 

          RX bytes:11241 (11.2 KB) TX bytes:11241 (11.2 KB)



wlan0     Link encap:Ethernet  Endereço de HW 10:08:b1:3b:3d:11  

          inet end.: 10.110.80.14  Bcast:10.110.255.255  Masc:255.255.0.0

          endereço inet6: fe80::1208:b1ff:fe3b:3d11/64 Escopo:Link

          UP BROADCAST RUNNING MULTICAST  MTU:1500  Métrica:1

          pacotes RX:19710 erros:0 descartados:0 excesso:0 quadro:0

          Pacotes TX:1455 erros:0 descartados:0 excesso:0 portadora:0

          colisões:0 txqueuelen:1000 

          RX bytes:2757117 (2.7 MB) TX bytes:218735 (218.7 KB)







$nm-tool



State: connecting



- Device: wlan0  [SmartCampus] -------------------------------------------------

  Type:              802.11 WiFi

  Driver:            rtl8723be

  State:             connecting (configuring)

  Default:           no

  HW Address:        10:08:B1:3B:3D:11



  Capabilities:



  Wireless Properties

    WEP Encryption:  yes

    WPA Encryption:  yes

    WPA2 Encryption: yes



  Wireless Access Points 

    Tatane:          Infra, 00:26:F2:52:53:D7, Freq 2462 MHz, Rate 54 Mb/s, Strength 30 WPA WPA2

    JH cherche JF plutot canon: Infra, 88:9F:FA:0F:E7:35, Freq 2462 MHz, Rate 54 Mb/s, Strength 40 WEP

   NUMERICABLE-6B42:Infra, 24:EC:99:FF:A8:CB, Freq 2452 MHz, Rate 54 Mb/s, Strength 40 WPA WPA2

    SmartCampus:     Infra, E0:1C:41:AB:80:54, Freq 2437 MHz, Rate 54 Mb/s, Strength 35

    NUMERICABLE-1AB1:Infra, 00:1A:2B:9B:1F:01, Freq 2462 MHz, Rate 54 Mb/s, Strength 37 WPA WPA2

    Livebox-1E06:    Infra, 40:F2:01:5E:1E:06, Freq 2462 MHz, Rate 54 Mb/s, Strength 34 WPA WPA2

    NUMERICABLE-CAAC:Infra, 00:1A:2B:6C:B1:DC, Freq 2462 MHz, Rate 54 Mb/s, Strength 44 WEP

    FreeWifi:        Infra, 14:0C:76:70:C5:82, Freq 2462 MHz, Rate 54 Mb/s, Strength 57

    SFR WiFi FON:    Infra, AA:17:33:E0:E7:91, Freq 2462 MHz, Rate 54 Mb/s, Strength 74

    SmartCampus:     Infra, E0:1C:41:AB:7F:94, Freq 2462 MHz, Rate 54 Mb/s, Strength 100





- Device: eth0 -----------------------------------------------------------------

  Type:              Wired

  Driver:            r8169

  State:             unavailable

  Default:           no

  HW Address:        34:64:A9:75:FF:7A



  Capabilities:

    Carrier Detect:  yes



  Wired Properties

    Carrier:         off