In PnP a GM can roll multiple dice at once. On a computer, even a 486 is capable of performing the same outstanding feat.
And no, it didn't. The game's great atmosphere was created by good sound effects, good music and good vision in creating the blasted look of the buildings. It was not helped by interminable waiting.
The game's got flaws, all games have them, including the mighty Fallout franchise. In fact, Fallout had more than most. This combat lag was, in my opinion, one of them.