you could try this utility...http://www.softpedia.com/get/System/...-Utility.shtml
pretty simple, user-friendly.
when i got my AMD64 3000+ @ 1.8Ghz system 20 months ago, i was confused about that reading too..
in System Info it would only read 800mhz, but after i installed a CPU clock reader (and set the power management to "Always ON", the clock read it correctly at 1800mhz. even tho would still say 800mhz through windows.
CPU's will throttle up to meet the demands of your program or throttle down to just utilize what you need.
hope that helps.