They should run at 2.8 GHz, which is their Turbo speed. For this to work, you'll need to check if any settings regarding power/energy saving are active. Check your BIOS first for any of these and set them to maximum / disable any throttling or power saving features. If it still won't work, check the "Power Options" feature in Windows' control panel and see that the performance plan is set to maximum/high performance (i.e "Hoechstleistung" in german ).