Present and/or future. The only thing you want to mention having happened 'in the past' is the work you did to improve your prespect's future.
It's the old Features and Benefits thing: People think they are interested in Features, but what they really will buy are Benefits.
Example 1 :
1. - New CPU improving performance
2. - New CPU improves performance A better-performing computer is a feature. You want to emphasize the benefit- i.e. the user is more productive (unless you mean the user's performance is improved).
3. - New CPU improved performance
Example 2 :
1. - New CPU achieving higher performance2. - New CPU achieves higher performance Similar; not as good as your Example 1, but better than the other two here.
3. - New CPU achieved higher performance
Example 3 :
1. - Lightweight design giving you less stressThis only works if it is part of a longer statement.
2. - Lightweight design gives you less stress A good Feature (lightweight design) and Benefit (less stress) statement.
3. - Lightweight design gave you less stress (I can tell this is wrong.)
Student or Learner