When moving at a speed greater than half but less than your normal speed, you take a –5 penalty. It’s practically1 impossible to [use stealth] while attacking, running or charging.
However, none of the rules make any mention about stealthing at normal speed. It is neither impossible, nor is a penalty given. Is there any errata or obscure rule for either system which gives a more official ruling?
1 - Pathfinder rules say it's impossible, and D&D rules say it's practically impossible, imposing a -20 penalty.