If it's an AMD Athlon64 3000+ it should be either 1.8GHz (sockets 939 and AM2) or 2.0GHz (socket 754), while an AMD Sempron 3000+ is normally 1.6GHz (socket AM2) or 1.8GHz (socket 754).
Now, more information about your processor, including the socket type and current clock speed, can be found out using a number of programs, with the free program Everest being my preferred choice. You should know if it's overclocked or not, but this way you can check the current speed to verify its normalcy.
Hope this helps,
I have a Amd 3000+.. I wanted to know what my clock speed should be and make sure i am not overclocking. thanks for the help