Rendering bugs in acad 2007

[Macpod]

I was doing some stress test, rendering a large scene with compound curves and full lighting. the first go produced something that was abit like a dogs breakfast. second try yielded the dreaded 'ghosting'-tail appears n screen when i drag a toolbox, and it didnt refresh. A third try after a restart yielded a black rendering window. although similar scenes have worked before.

 

Im on a new E6600 with 2gb ram and geforce 7950 so i dont think its the system resources.

 

Has this been a problem with anyone else?

 

 

 

PS same scene can be rendered in 3 seconds in 3dmax 8.