Computer Speed – Then and Now


I was going through some old CDs today. On an album from 1993 I found this Mandelbrot fractal image. The authors were so proud of it that they gave a lot of details in the liner notes, which allowed me to recreate it and do some speed comparisons.

I was amazed.

Cover art generated by Lawrence S. Kroll, Professor of Computer Science at San Francisco State University. Dr. Kroll generated the fractal over a period of 4 1/2 hours on a Macintosh Il computer. This particular graphic image was rendered with a total of 640,000 points. Each point on the computer screen took up to 3500 computations to achieve high resolution. This comes to over 2 billon calculations for the one image. Typical times to generate this same image are: IBM PC or Mac Plus: about 4 days (day and night), CRAY X/MP Supercomputer: less than 10 seconds.

640,000 data points sounds like a lot, but it’s not. It’s only 800×800, or .64 megapixel. Your phone (depending on the age or model) is between 3 and 12 megapixel.

Likewise, 2 billion calculations sounds like a lot, but it’s not. CPUs are measured in MIPS (Millions of Instructions Per Second) and a modern Intel I7 CPU, like a typical gamer’s PC is rated at 317,900 MIPS – nearly 318 Billion instructions per second.

Yes, there is more than one “instruction” per “calculation”… But get real. The CRAY Supercomputer from 1993 doesn’t even make a good web browser these days.

For fun, I used a copy of XaoS software on my 2010-model MacBook to generate that same image today. I didn’t time it precisely, but it took around 1 second – on a 7-year-old laptop.

If you want to try it for yourself,  fun fractal software is available for your iPhone, iPad, Windows and Mac.

For anyone wanting to recreate this test, they listed the exact parameters of this fractal as:

The Fractal Location for this image is: center: x -0.7454286; center: y .11300881; magnify 2 x 10 times; Escape Radius- 2.5, Dwell 1000.



Written by David Finster

Technical consultant and computer support. Text or call me for your tech support needs: 941-444-9771