Dell Latitude E6400 - User review

Now that's definitely an entirely different noise. Noise only at high performance wouldn't have been an unbearable issue for me because I tend to keep the CPU frequency down. I'm also sure yours is a lot more quiet. Well, that's some of my frequent bad luck, hopefully I can circumvent it soon

And no, I didn't guess your noise comes from the speakers. Its just the case with my dad's slightly overpowered Acer notebook (he thought that he needs lots of graphics memory for multimedia presentations...), which isn't that well-engineered...

 

New update on the sound of the CPU
This sound can NOT be heard in a class room even if you have your head on the keyboard.. I tried. Even setting the machine at High Performance with the power adapter. You really, really, need to be in a quiet room and concentrate no that sound.
So another words it's not an issue.

 

Here are the results:

Using 65W PSU
CPU Speed: ~600 MHz
CPU multiplier: 6.0x
CPU FSB: I forgot to check

Using Laptop Battery (system set as high-performance)
CPU Speed: ~800 MHz to 2245 MHz
CPU multiplier: 8.5x
CPU FSB: 92 MHz to 266 MHz

Using Laptop Battery (system set as power-saver)
CPU Speed: ~784 MHz to 800 MHz
CPU multiplier: 6.0x
CPU FSB: 131 MHz

Using 90W PSU
CPU Speed: ~2325 MHz [original: 2266 MHz] (Auto-Overclock itself up to 3%)
CPU multiplier: 8.5x
CPU FSB: 274 MHz [original: 266 MHz] (Auto-Overclock itself up to 3%)