In 3D modelling the model is updated every time a change is made. This is because the computer has to decide whether the extra features or cut-outs form a concave or convex appearance, how much they affect the volume, and how it looks on the screen. If it didn't do this every time a change was made, the representation on the screen would not be accurate. Some software saves time by not updating blueprints until the model is finished. Nevertheless there is a noticable wait while the computer processes a command, say, if the model has a few hundred features (ribs, holes, swept profiles, lofted surfaces, etc). I have frequently noticed a delay of up to 3 minutes while the computer processes commands. At that point I am very careful what changes I make so I don't waste time. But it all adds up, especially if the math module can't adequately process a particular feature and I have to work around it. If the computer crashes that makes it bad too. Overall things take twice as long as expected.

A faster computer would definitely be worthwhile, just as worthwhile as a stable operating system. Knowing this fact however, management expects a direct relationship between an increase in computer speed and worker productivity, and it just doesn't happen. That upsets everyone, including the guy tending to daydream about his latest female conquest while his boss hovers over him with a pink slip shouting orders over his shoulder.