Please write about:config on the adress bar and press enter.

network.http.pipelining find it and change its value to "true"

network.http.pipelining.maxrequests  find it and change its value to "8"

network.http.proxy.pipelining find it and change its value to "true"

network.dns.disableIPv6 find it and change its value to "true"

plugin.expose_full_path find it and change its value to "true"

After all of these modifications, the adding new integers turn. Right click anywhere you want and click new/integer and spesify the name of the new integer.

These are the new integers;

• nglayout.initialpaint.delay is the name of integer and please make its value "0"
• content.notify.backoffcount is the name of integer and please make its value "5"
• ui.submenuDelay is the name of integer and please make its value "0" 
• browser.cache.memory.capacity is the name of integer. And the value of that integer is depends on what size RAM you want to use. I want 32MB that’s why i make its value "32768" You can change the value whatever you want firefox to use your system RAM.

After all of these steps you restart your system.