剛好找到有人在這邊有說明
http://forums.pimprig.com/archive/topic/16473.html

FSB Spread Spectrum
Reduces the EMI of the FSB by modulating the signals it generates so that the spikes are reduced to flatter curves. It achieves this by varying the frequency slightly so that the signal does not use any particular frequency for more than a moment. Disable if you are doing any overclocking.

AGP Spread Spectrum
Reduces the EMI of the AGP bus by modulating the signals it generates so that the spikes are reduced to flatter curves. It achieves this by varying the frequency slightly so that the signal does not use any particular frequency for more than a moment. Disable if you are doing any overclocking.

這兩項就如樓上i兄說的用以降低EMI用的....

CPU Thermal-Throttling
Downclocks and disables certain parts of the CPU while idling to reduce power consumption and lower termperature. Unless your system idles alot or you have heat issues, disable it.
大意是說降低cpu的速度並減少電力的浪費, 獲得較低的溫度。除非你的電腦大部分都處在閒置的狀態，或是有cpu散熱問題的人，就啟用它，反之就停用它。