CPU Clock Speed is lowered when battery is detached - ThinkPad
System CPU Clock speed is lowered while when battery is detached from the system.
The following ThinkPad systems maybe affected by this symptom:
Edge 13, Edge E30, Edge E120, Edge E320
R60, R60e, R61, R61e
T60, T60p, T61, T61p
T410, T410i, T410s, T410si, T510, T510i
T420, T420i, T420s, T420si, T520, T520i
W500, W510, W520, W700, W700ds, W701, W701ds
X61, X61s, X61 Tablet
X200, X200s, X200 Tablet
X201, X201i, X201s, X201 Tablet
X220, X220i, X220 Tablet, X300, X301
Condition may occur when system battery is removed and powered with a 65 watt AC adapter that the CPU clock is lowered to prevent accidental shutdown. If maximum frequency operation is preferred in such situations, a 90W AC adapter should be used.