PowerBooks: Scrolling Speed - Color vs Black & White (1/95)



I have a PowerBook 170 which I want to replace with a PowerBook 280c. However, I cannot understand why the text scrolling in Microsoft Word 5.1 on the PowerBook 280c seems slower than on my PowerBook 170. On the other hand, I found that the performance of Microsoft Excel is faster on the PowerBook 280c than on my PowerBook 170.

I understand that the PowerBook 170 and the PowerBook 280c are each running at different processor speeds and operating on different system software, but could you provide a technical answer describing why the scrolling on PowerBook 280c seems slower?

The reason why scrolling may appear faster on a PowerBook 170 is due to the color, or lack thereof. A PowerBook 170 can only display black and white, so a pixel on the screen of a 170 is represented by 1 bit. A PowerBook 280c can display 256 colors, so a pixel on the screen of a PowerBook 280c is represented by 8 bits (16 bits in thousands of colors). This means that QuickDraw has to keep track of that much more information when scrolling which makes it slower.

A better comparison in performance would be to set the PowerBook 280c (or any PowerBook whose screen is set to display grays or colors) to black and white using the Monitors control panel, and then compare application performance. This will give you a truer comparison of the actual processing speed of each machine.


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Published Date: Feb 19, 2012