1. Ketik, “about:config” di Addresse bar (URL) trus ENTER.
2. Cari en ganti settingannya kaya dibawah ini: (kalo belon ada, bikin dulu --> klik kanan - new-...)

Change this :
browser.tabs.showSingleWindowModePrefs – true
network.http.max-connections – 64
network.http.max-connections-per-server – 20
network.http.max-persistent-connections-per-proxy – 10
network.http.max-persistent-connections-per-server – 4
network.http.pipelining – true
network.http.pipelining.maxrequests – 100
network.http.proxy.pipelining – true
network.http.request.timeout – 300
nglayout.initialpaint.delay = 0
network.http.request.max-start-delay = 0
If nglayout.initialpaint.delay doesnt exist, Right click, new integer.
network.http.max-persistent-connections-per-proxy = 10
network.http.proxy.pipelining = true
network.http.proxy.version = 1.0

3. Tutup firefox kalian, trus buka lagi.
4. Selamat menikmati speed yg bertambah :)