First all of all speedstep is working. You said you have a 6x multi but when you run a stress test its the only way to increase the cpu speed. That IS speedstep.
Just reset all your BIOS settings to default. And leave them alone until you know what you're doing.
Once the settings are reset run cpu-z. When idle it should be 6x. Load up any type of cpu test or a demanding app and make sure it goes up. If/When it does just leave your system alone.