all kind of graph editor slows down

i was using the node editor.
when i used scroll wheel in the node editor
it takes too much of time to zoom in and
out.
it is lagging too much to zoom in. and the
response time decteases when i move the
cursor into any of these wpanels.
i tried to narrow down the reason and i
ffound the same problem with logic bricks
panel node editor timeline and all the
graph editors. the common thing that i
found is they are based on graph except
the logic bricks editor.
i think i have given all thr clues to trave the
reason.
i am using windows 7 32 bit.
can any body help me?
thank you…

Hi

Ctrl + mmb…Drag to Zoom

Tai