There are ways to control laptop fan noise, at least for some models.
First off, try looking in the BIOS for any fan speed control settings; a long shot but worth a try.
Secondly, there is software that allows you to tweak the relationship between fan speed and temperature. A lot of Dell models support this particular software:
Thirdly, reduce the amount of heat that the CPU generates. You can do this in a number of ways:
Make sure that Speedstep is enabled even when using A/C power. To do this you will either need to change a BIOS setting or use a software utility such as RMClock http://cpu.rightmark.org/products/rmclock.shtml
Use software such as RMClock to reduce the voltage of the CPU at various clock speeds. You may also be able to use this to reduce the maximum clock speed of your system. E.g. If you reduce it from 1.66 to 1.5, it could just be enough to keep the temps at a comfortable level so that the fan doesnâ€™t need to go into overdrive.
A laptop that supports all these utilities may be able to work much more quietly, provided that it has a well designed cooling system in the first place. Sometimes itâ€™s just a matter of manufacturersâ€™ setting their fan speeds very aggressively out of caution.
Please let us know if any of this helps and whatâ€™s the screen like on the 6400?