Core 2 Duo Processor image thumb1 It’s no secret, the modern-day processor race isn’t measured so much on how fast the processor is, but rather how many cores you have.  First we saw the Core Duo (2 cores) processors, then the Core 2 Duo’s (4 cores).  While your inner-geek can certainly brag about the number of cores inside your machine, what about actually using them for some real processing?

A lesser-known AutoCAD System Variable might just be your ticket to utilizing some of that extra power.  The system variable is WHIPTHREAD.  Depending on how you set this variable, AutoCAD can use that extra processor to improve the speed of operations which require a redraw or regenerate the drawing such as ZOOM.  I have copied an excerpt from the AutoCAD help file, documenting what each value does:

0

No multithreaded processing; restricts regeneration and redraw processing to a single processor. This setting restores the behavior of AutoCAD 2000 and previous releases.

1

Regeneration multithreaded processing only; regeneration processing is distributed across two processors on a multiprocessor machine.

2

Redraw multithreaded processing only; redraw processing is distributed across two processors on a multiprocessor machine.

3

Regeneration and redraw multithreaded processing; regeneration and redraw processing is distributed across two processors on a multiprocessor machine.

It may seem pretty obvious, but the WHIPTHREAD system variable has no effect on single processor machines.  Additionally when you have WHIPTHREAD set to 2 or 3, the order of objects specified with the DRAWORDER command may get mixed up.  According to the AutoCAD help file, DRAWORDER is preserved for plotting.