Issue: Volume: 24 Issue: 3 (March 2001)

G4 versus PIII

By Joe Greco

Ever since the introduction of Apple's Power Macintosh with the Motorola G4 processor, many articles have compared its speed to top-of-the-line Intel-based PCs. However, most of the speed tests have involved 2D graphics programs such as Adobe Systems' Photoshop. Some attempts have been made to rate the Mac's 3D performance (see "Rating the Power Mac G4" on pg. 65 of the July 2000 issue) but these have been relatively few and far between. Therefore, I decided to test the machine's performance on some common CAD applications.

Apple sent an OS 9-based 500mhz dual-processor G4 with 256mb of memory and a 40gb, 7200-rpm Ultra ATA/66 hard disk. Graphics were controlled by an ATI Rage Pro accelerator with 16mb of memory.

I also tested a single-processor Dell Precision 420 with the same amount of memory. The lack of dual CPUs wasn't an issue, as none of the programs tested currently take advantage of this architecture anyway. The Dell ran at a higher clock rate, 933mhz, but because of the different technology behind each processor, the mhz numbers are not a meaningful benchmark, especially for the purposes of this evaluation.

The Precision's graphics card, an Elsa Gloria II with 64mb of memory, was a bit more powerful than what was inside the Mac, so I made sure that the graphics tests stayed away from texture mapping routines, which is primarily what that extra memory is used for. This computer had a more modest 9gb SCSI disk, spinning at 10,000 rpm, and came loaded with Windows 2000.
A formZ bottle model was perfect for testing high-end rendering functions on both the PC and Mac.

Due to basic hardware differences, it is hard to compare Apples to, er..., PCs. So while the systems weren't an identical match, the main goal was to test what both companies considered their top-of-the-line computers for 3D graphics. Both machines sell for approximately the same-$3000.

One of the challenges of performing this comparison was finding 3D applications that run on both systems. Each platform has its share of fine programs, but few are cross platform. Overall there were about 10 mainstream applications to pick from, so I narrowed this down by choosing programs that focused on different disciplines, as follows:

FormZ for general modeling: This program from autodessys is a well-respected modeler and renderer for general-purpose 3D design-that is, everything from sneakers to furniture. Its uses are similar to that of a 3D Studio Viz on the PC or Strata 3D Pro on the Mac.

VectorWorks for AEC CAD: From Nemetschek North America (formally Diehl Graphsoft), this program has many uses, but is most popular with architects, because of its palette of 3D tools such as walls, floors, and roofs, as well its parametric library of doors and windows.

Vellum Solids 2000 for CAID and MCAD: This is a 3D version of Vellum, the program that Ashlar introduced in the late 1980s with several groundbreaking features that most CAD users now take for granted. Vellum Solids is aimed at both industrial and mechanical designers.

It should be pointed out that all of these particular programs started on the Mac and were then brought over to the PC. However, each company initiated Pentium development at least four years ago, so the code should certainly be mature.

The goal was to test the three main components of each system-the CPU, the graphics, and the hard disk. I talked to technical employees at each software company to see which commands tested which system components.

CPU tests: In formZ, I was informed that performing a raytraced-style rendering primarily taxes the CPU. So I opened a sample file called Bottles and ran the program's RenderZone command, using the default settings. I also did a hidden line removal, which drains both the CPU and graphics card evenly.

In VectorWorks, performing a Quick Draw 3D rendering is the best way to test the processor, so I opened a large architectural model and timed the results. Processor testing in Vellum Solids was achieved by modeling a tapering helix-shaped tube on both platforms.

Graphics: Testing the graphics card with formZ was easy, as it has an OpenGL rendering function on both platforms. I used the Bottle file again, but OpenGL rendered it so quickly that I needed to make 16 duplicates.

Whereas the routines of a hidden line removal in formZ were split between the CPU and graphics card, in VectorWorks this challenged the card more, so I rendered a hidden line image. In Vellum Solids, I used the command that automatically rotates the model, thus spinning the helix shape two complete revolutions (720 degrees) while it was rendered with Phong shading.

Hard Disk: In formZ, I was able to generate a 300-frame animation from three views that were already set up in the Bottle file, which resulted in a 51.1mb QuickTime movie file. In VectorWorks, I pretty much did the same thing, using the Create Animation command and leaving the default settings as is in order to create a 22.6mb movie file (27.8mb on the PC). Finally, with Vellum Solids, I selected the helix shape and duplicated it 16 times to create a 40mb file. Opening these files caused a lot of disk action as I clocked the entire launch time.

While it may smoke in Photoshop, 3D on the Mac still has a way to go. The Dell system was approximately 40 to 250 percent faster in the CPU tests and about 12 to 70 percent faster in all the disk chores. Surprisingly, in the graphics test the Mac did well in formZ and VectorWorks, but it did get completely outclassed in the Vellum Solids benchmark.

However, there are bright signs. Mac OS X is right around the corner and looks so promising that both LightWave and Maya, in addition to a host of other applications still being announced, will run on it. However, while OS X will improve Apple's situation in CAD and design, this could be counteracted by PC users migrating to speedier P4 systems. Personally, I am all for CAD users having another choice when picking an operating system, as long as it creates no new interoperability hurdles. When OS X finally ships, it should make for interesting times.

Joe Greco is a freelance writer specializing in computer-aided design. He can be reached at