When using ThrottleStop, first you need to increase the Set Multiplier adjuster until it says Turbo and then click on the TRL button to adjust your CPU's Turbo Ratio Limits or you can click on the TPL button to adjust the Turbo Power Limits.

If you still have multiplier throttling issues at full load, it might help you get over the hump. ThrottleStop should let you adjust the turbo multipliers from within Windows so if you are having a problem booting up reliably, you might be able to boot up at a reduced multiplier and then use ThrottleStop to take it higher.