3d Modelling performance issues

[ghost_uwi]

Good day

I have AutoCAD Civil 3d and when i render extremely large drawings (1 kilometer of data with a ton of points) it move pretty jerky when orbitting. The Specs on the Computer is

2 x X5650 Intel Xeon Processors
1 x Quadro 5000
32gb DDR3 1600 MHz RAM
10000RPM Velociraptor Hdd

However on a machine with lower grade specs
1 x AMD (6core) (not sure exact model)
1 gig 9800 GTX
16 gigs Ram
Solid State Harddrive

It runs smoothly.
Exactly what could be wrong with the higher end machine ?
Or Is this an AutoCAD Problem

[ReMark]

I was under the impression that rendering is CPU intensive so I guess one would have to compare the two systems in respect to the CPU(s) installed.