Look in Windows Control Panel > System and Security > Power Options (for Win 7, 8 should be similar). Set the power option to 'balanced' or 'power saver' instead of 'performance.' Balanced works well for my 24/7 settings, letting the CPU clock down to 800MHz when unloaded.
In BIOS, EIST - speed step - should be enabled. If Turbo is also enabled, CPU speed can step up at high load to 3.8 or 3.9GHz depending of model of i7.
I don't use AI Suite -- do all that setting in BIOS.
Jeff