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• PowerXplorer is a small application I wrote to test the PowerPC speed in native floating-point calculations. It draws the Mandelbrot set and lets you explore it by zooming in and out at will. The iterations may be increased (when there’s too much black in the image) or decreased.
• PowerXplorer is a “fat” application: it contains code for both the 680x0 processors and the new PowerPC chip. The 680x0 code requires at least a 68020 and a 68881 coprocessor; it doesn’t run on a 68LC040 because that chip has no math coprocessor. PowerXplorer requires 256 colors (or grays) to display the images properly; with thousands or millions of colors the image is correct, but there’s no color animation.
• PowerXplorer can display the actual time required to compute an image if the Caps Lock key is down when drawing is over (or if you type cmd-D). All screen drawing and other toolbox calls are excluded from the total time shown so you can test a machine’s speed without worrying about its video card or the 57 extensions in its System folder.
• Two “test” images can be invoked by typing cmd-T or cmd-Y. These images take much longer than the default set to draw, so the speed measurements are more accurate. Typical values for a Power Mac 6100/60 on a 640x480 screen are 2.04 seconds for the whole set and 22.83 seconds for the first test image. A Quadra should be about 7 to 10 times slower, whereas my Macintosh IIcx is about 100 times slower (39 minutes for the first test image). Here’s a list of the timings I could measure in a 640x480 window:
Machine CPU/Speed Whole Set Test Image 1 Test Image 2
Macintosh IIcx 68030/16 188.26 2341.49 2166.91
Macintosh Quadra 700 68040/25 20.57 223.23 207.14
Power Mac 6100/60 601/60 2.04 22.83 21.10
• PowerXplorer checks for keystrokes or mouse clicks after each chunk of the image, but not during the calculations; on slow machines you may have to wait for up to 30 or 40 seconds before a command (like cmd-Q for Quit) is acknowledged.
• Comparing the speed of a 680x0 Mac to that of a Power Macintosh is no easy task, because their code comes from two separate compilers which may have different optimization capabilities. The 680x0 code in PowerXplorer was generated with Symantec’s THINK C 7.0, whereas the PowerPC code comes from an alpha release of Apple’s PPCC compiler for MPW.
• SORRY - there’s almost no user interface in PowerXplorer because my usual application framework would take forever to compile under PPCC. If I can ever buy Metrowerks’ Code Warrior Gold and if it works, this quick and dirty test may well get its menus and windows like all my other programs…
• PowerXplorer may be freely distributed by anyone on any media or network, but it is not in the public domain - I retain all rights to it. You can send me a postcard or a letter if you really like it.
