Well, it runs fine, rarely crashes too. I use it to mess around with the tutorials and such. Just now starting to notice lags as i get into volumetrics, particle emitters, and High-res UVMaps.
Most of my projects are small. I'll have a new machine by the time i am ready to take on any bigger projects. Out of curiosity, how big do your working object files get?
The noticable difference is when I render; Animations that take my office machine (also a P3 850) ~4s/frame to render take 2min+/frame on my laptop!
