Testing and choosing a host for increase the speed

hi folks
I'm going to choose a best host for increase speed and performance but I am in doubt with How I can recognize why my site is slow ? is there any way to find out why it is slow I don't want to copy all files in the new host and then understand it is not related to host service is there any program or consol to test the site and understand this things ?

From serverfault Kamiar

• How I can recognize why my site is slow ?

  Use Chrome Developer Tools: http://www.chromium.org/devtools

  and

  Use top/htop on the server: http://www.howtogeek.com/howto/ubuntu/using-htop-to-monitor-system-processes-on-linux/

  is there any program or consol to test the site and understand this things ?

  Easy tools - Apache HTTP server benchmarking: http://httpd.apache.org/docs/2.2/programs/ab.html

  or

  SIEGE(can use url files): http://www.joedog.org/index/siege-home

  Kamiar : I use Windows OS.

  bindbn : Use chrome(development tool) and JMeter(http://jakarta.apache.org/jmeter/usermanual/get-started.html)
  From bindbn