computer slowed down after installing new cpu

i just put a new
Model: Intel Pentium 4 w/ Hyper Threading
Operating Frequency: 3.0GHz
FSB: 800MHz
Cache: L1/12K+8K; L2/512K
Socket: Socket 478

this is fairly close to what my old cpu but checking in my bios it is running at only 1.5ghz

from what i have heard from various sources is that i need to change mannually change the jumper which of course i don’t know where it is located on my laptop or how to find it