When i set the enviorment plans to model, (top and side), all looks to work fine, but when i begin to model in nurbs, and create at least one simple figure, and i turn to an orphographic view, when i zoom or move, it really gets very very slow... whats that? any1 help plz ...

ps: pc= amd3000 64;, ati radeon 9800xt 256m, 1,5gb ram.. it shouldnt work bad ..