Hmmmm? VirtualBox doesn't like Intel?

[kitepilot at kitepilot.com]

Sometime ago I got to virtualize this bare-metal WinXP laptop under *Ubuntu 
and I was happy.
Later on, the performance proved to be unbearable (processor pegged at 100% 
load 100% of the time) and I was unhappy. 

Life went on.
Bug went itching...
Geek sprung into action and:
I vdi(ed) the laptop's HD and fired up a run-of-mill VM and...
surprise, surprise... 

VirtualBox running in this AMD-64 processor (not sure what, research still 
not in full swing) runs my Virtual XP juuuuust fiiiine... 

Same VM running on the Intel "Core Duo" of the laptop, SUUUUCKS! 100%... :( 

4GB RAM both machines, *Ubuntu 10.04.
Does this make any sense?
ET