Then I'd think the hack needs to come out and bash some then a visit of the BIOS may be called for. Also look in the brand driver programs. Those is what I needed to convince it to stay on max, first using the "Rightmark CPU clock utility" aka RMclock to force the hand.

--//--

edit: Still got RMclock on the machine and when running it shows as options:

No management
Power Saving
Max performance
Performance on demand

It's a mighty fine tool with battery management features and a "throttle" control page. Later I could drop the use when getting the Sony Vista drivers back in.

Thanks Martin - that certainly seems to be what's causing this issue. Currently though, as I'm (curtesy of IBM), seeking new employment, splashing out over £60 on a higher spec adaptor is out of the question for me - so, I'll just have to either crunch approximately half the number of WU's for the same amount of time, or risk frying my laptop... Guess which option I'm going to do...

Anyhow, for future reference, here are the details of that higher spec adaptor;

General
  Part number 40Y7667 
  Description ThinkPad 90W AC Adapter - UK / Ireland / Hong Kong / Malaysia / Malta / Myanmar / Singapore / Brunei / Saudi Arabia Line Cord

Power management
  Connector Description 3-pin AC 
  Input Voltage 20.0 
  Power 90 W 
  Power supply type 100-240 volt AC 
 
Limited warranty[7]
  Limited warranty period One year 
 
Technical Information
  Supported Software Applications
    ThinkPad Edge, L410, L412, L420, L421, L510, L512, L520, R60, R60e, R61, R61e, R61i, R400, R500, SL300, SL400, SL410, SL500,
SL510, T60, T60p, T61, T400, T400s, T410, T410i, T410s, T410si, T420, T420s, T500, T510, T510i, T520 Dual Core Models, X60, X60 
 
Environmental Information
  Maximum Operating YYYY 80 % 
  Maximum Operating Temperature 40 C 
  Minimum Operating HumidityXXX 8 % 
  Minimum Operating Temperature 5 C 
 
Architecture
  Depth Metric 126 mm 
  Height Metric 30 mm 
  Height US 1.18 in 
  Weight Metric[2] 0.360 Kg 
  Weight US[2] 0.79 lbs 
  Width Metric 50 mm 
  Width US 1.97 in