Why the CPU speed changes weirdly?

Question

My machine is I9300 with PM 1.6G/800M. I found the CPU speed changes weirdly.   When the machine is powerd by battery, for each time of first bootup and entering Windows, the current CPU speed showed in the syetem property ( in control panel of Windows  is 798MHz. And it keeps on this speed, sometimes even lower, never reachs 1.6GHz. But each time I reboot the machine, the speed changed to 1.6GHz, and keeps on it.   So I enter BIOS, the current speed showed is 800MHz. The strange thing is if I browe the BIOS for a little while and go back to the first item for CPU, the current speed changed to 1.6GHz.   This problem occured when the fast boot in BIOS is enabled( default setting  . If I disable the fast booting, make it bootup slowly. The the CPU speed is always on 1.6GHz, no matter it's the first bootup or reboot.     My friend has an I8600, He has the same problem.   Thanks

Chunhui Mei · Answer

How does it adjust the speed according to the work load? Higher speed for higher work load, or higher speed for lower work load?   And why is the speed in the first bootup different with that in the reboot?   Thanks

RRF985 · Answer

SpeedStep changes the CPU speed based on how much load is on the system.  You can get SpeedSwitchXP to force the CPU to run at full speed.

dsbInspiron · Answer

It adjust to a higher speed for a higher work load. This will supposedly save your battery b/c the processor only runs at full when need be. I would definately download that program, you can set it to run on AC or Battery or to Switch like it is now.

"And why is the speed in the first bootup different with that in the reboot?"

Another mystery of the Intel world. You could poke around Intel's site and see if they have any answers.

db

powderoo · Answer

Hey,,before you down load every little program some one in this forum tells you to, make sure it is supported by dell, as to not void your warranty.  Nothing like having a $1,600 paper weight.

RRF985 · Answer

IMO no harm can come from running this program.  All it does is force the CPU to run at max speed.  Therefore it won't void the warranty.

Chunhui Mei · Answer

But it seems the speedswitchxp doesn't work on my machine. how to use it?

RRF985 · Answer

Open it and then select max. performance while it's  plugged in.

Locked Topics – Laptops General

Why the CPU speed changes weirdly?

Was this post helpful?