Lag Scrub

Thats what the title says, how can i speed things up…? Should I buy a off board sound card and video…? My scene is not complex and still having too much lag, got a great pc config (E8400 C2D 2gb Ram, WinXP32, integrated video and sound) already take the subsurf off, using just one layer and still lag remaiins, I did the search but didnt find anything that gave me a good answer…

Blender doesnt make realtime playback or scrub that´s all that I read I think that´s a big issue and could have a decent answer from coders or people that know more deep the software dont you thnik…?

Ok, its a bug on 2.49a because I just catch 2.48a and it works with no lag the scrub…so if anyone is searching what can do to fix, go back to 2.48a when there´s the need to use realtime scrub…