I can't get the CPU to exceed 798 MHz which is supposed to be its Minimum speed according to the Bios.  The processor is a Pentium M 750 (Supposed to run @ 1.86 GHz).  The bios confirms the max speed to be 1.86 GHz but it never reports it running that fast.  I have tried all the power modes and profiles in WinXP and the Dell QuickSet application.  I have also tried to force "Max. Preformance" with SpeedSwitchXP but no go.  

SpeedSwitch reports 798 MHz so does windows when I check system properties.  Intel Processor Identification Utility reports an expected Speed of 1.86 GHz and a reported speed of 0.79 GHz.  I am running Folding@Home and playing a 1080i encoding of a Planet earth episode to force the processor to 100% and the video is skipping a bit so the system should be maximizing the CPU frequency.  I am plugged in to wall power.

Perhaps a thermal issue is preventing this?

Did you check the frequency during the time it was at 100%?
I bet most systems would stutter playing 1080i video and F@H.  F@H maxes your cpu without the help of video playback.  

@Rodney_ws
Dell actually just replaced the fan and Heatsink assembly.  I don't know how to check the temp of the chip though.
 
@KingOfTheRings
I did check the frequency at that time with all 3 methods.  F@H will step out of the way when another program needs the processor it runs at the lowest priority level an only uses Idle cycles, however it will use 100% if nothing else is which makes it a productive way of making sure your processor is maxed out.

 
Find a utility called RMclock, or RightMark CPU Clock Utility.  I dnl'ed this while trying to figure out how to best OC my Dell M1330.  It is a neat utility that displays your CPU speed and activity on the taskbar so you can gauge its usage.  It is normal for the CPU to be slower even when plugged in as I can see with mine being only about 1.08Ghz but jumping up to 1.8 -2.0 when it has do some work.  The whole thing is tied to speed step and the CE1 halt states in the bios and chipset.  I have tried disabling those but found that it just locks the CPU down at the low speed and will not throttle up?  
 
If anyone has a good notebook OC software utility out there, let me know, still working on it.  Oc'eing the GPU was easy.

It's Speedstep, disabling it in the bios will force it to run at it's lowest setting all the time.
 
If you want to have the cpu running at full speed all the time download RMClock and in the advanced settings tab disable Enhanced Halt state.
http://cpu.rightmark.org/download.shtml
 
As for temps. you should be able to use Intels Thermal Analysis Tool or Coretemp to check them.
http://www.techpowerup.com/downloa [...] _Tool.html
 
http://www.softpedia.com/get/Windo [...] Temp.shtml
 
These programs worked on my XPS Gen2 which is basically the same machine.
 
Too   slow again

Thanks All.  I'm going to go try these suggestions right now.

Thank you all.  Problem solved!  RightMark to the rescue.