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How users perceive performance, and does that apply?

By:David K. Every
©Copyright 1999

One of the illusions that has harmed Mac in some PC users minds is "perceived" performance (as opposed to real performance).

Perceived performance is which machine feels faster. If you ask PC people, they will almost always answer PC's (to them) and if you ask Mac people it can vary. The Mac doesn't always feel as fast as is really is - that is because the UI is better and more fluid, and so people don't notice the UI as much. This smooths the users perceptions of going from one thing to another, and that fluidity is not as "jarring" or noticeable - this alters people's perceptions. So fluidity works against the Macs perception - people notice the Macs ease of use and better UI - but not the speed - because it is not in their face. Yet if you do work on both, after a while people are more likely to realize that they get more done on the Mac. So their initial perceptions are diametrically opposed to reality (and users more experienced perceptions). For more information on UI, see the sections on User Interface - and realize that many things that make the Mac have a better UI, make the performance less intrusive (and may make the Mac speed less noticeable).

In user interface design you learn that users are sometimes the worst gauges for performance. Many people feel they are working slower - while the stop watch proves they are working much faster - and with fewer errors. In general Apple caters to their real work performance - and MS feeds their fallacies and gives users things that make them feel like they are working faster - when in reality they are working slower. Some examples of where users perceptions are opposed to reality on the PC, include the following -

  • Mouse Speed. The PC mouse feels "hyper" compared to the Mac mouse. I have changed the mouse settings on a Mac to be faster, and users will say "Wow, this system is fast". In fact their errorrates on hitting targets goes up, and they are lessproductive - but they think it is faster.
  • Zoom-Rects. The Mac has something called zoom-rects. When you open (or close) a file, folder or window, rectangles fly open (or closed) giving an animated effect. This gives users some transition between closed and opened and shows where a window came from (or where it has gone to). It is an important UI effect. If you turn them off on the Mac, or a Mac user goes to Windows, they THINK the system is faster - there is no transition and so everything is surprise - "Wow, that window just appeared". Of course the system is not really any faster, and because users have more discontinuity in their work, they often lose productivity (if they don't know where a file went when closed, they occasionally have to search for it, etc.).
  • Scroll limiting. If you have a small window, you can often scroll the information by so fast that you can't see what is there. This means that scrolling is much harder because you can't actually hit where you want to be. The Mac limits scroll speed so it is more consistent on small and larger windows, and never scrolling so fast that it is unusable. This makes it appear the Mac is slower, and when users go to a PC they see scrolling windows that just fly (if they are small). But if you actually test there ability to find something or scroll to something without "overshooting" their target, they actually lose in productivity and are slower overall. The Mac also uses a progressive scroller, that scrolls faster and faster, unless the user releases the scroll for a bit - meaning they are getting closer to their target. So the Mac allows it to go as fast - just not jump from 0-mph to 1,000-mph in one jump (killing everyone in the car).
  • Forgiving nature. Users tend to blame UI issues on themselves. If Microsoft puts the delete key next to the save key, and a user misses and deletes their work, they blame themselves. The reality is that it is a bad UI design that cost them in productivity. When users factor performance they look at the advantages of having that shortcut key for the 1 time that they needed it, but forget to factor that against all the errors they made because of that "shortcut". So they think that it was faster - in reality it cost them far more than they gained. Macs tend to have many fewer of these gotcha's, and most Mac UI types know to weight the good against the bad in these types of functions - PC UI types are more likely to believe in features above reason (or usability).
  • Unfair comparisons - Mac users are used to ripping speed for certain Apps. Yet other Apps are emulated and only about the same speed as PC Apps. Yet if the users perception are based around those very fast Mac apps - then the user expects the Mac usual performance, and when instead gets an emulated apps performance (or something that is only running the speed of a PC) then the contrast will make him beleive (incorrectly) that this Mac app is slower than the PC app. The reality is that the emulated App may even be faster than the PC app. (This is the same thing as if you are driving 45mhp and speed up to 65mph, the passenger percieves that they are going much faster than when you take the same passanger and slow them down from 85mph to 65mph).

These are just a few prime examples of perceptions vs. reality, and how it works in favor of the PC and against the user. There are also other areas where Mac users perceive that the PC is slower. However, often these areas are more likely to effect productivity. For example -

  • Window Updates. On the PC's switching from one application to another can take an excruciatingly long time for the App to redraw all the parts of its window. You can watch the system jump around painting differerent parts of different windows (especially if you don't have enough memory). Macs usually just blast all the graphics changes at once to update a window (going from one app to another) - and often Macs 2 or 3 classes of processor slower are actually faster than PC's. Pentiums are now fast enough that this is less important - but it still takes a fast Pentium to be close to Macs that are 5 or 10 years old.
  • Menu Updates. On a Mac you can hold the mouse button down and wiggle back and forth across the menu's - the system responds with the menu's just updating instantaneously. If you can do the same thing on a PC (which is harder because of the PC's inferior menu design (see Understanding UI - Menu's) you notice that they are much slower than the Mac in most conditions. Though computers have progressed so much in performance that this is no longer becoming important (even PC's are fast enough - NOW). But it made a big difference for many years.
  • Keyboard Shortcuts. There have been a few studies on Keyboard Shortcuts that show that users are almost always faster with the mouse and menu's (with the exception of a very small sub-set of oft. used shortcuts) - yet the users almost always feel that the keyboard shortcut was faster. The reason is that when using the shortcut, users do a little mental look-up, while doing that look-up for the key, they are in an altered state of time-perception. They do not realize that time is passing because their brain is distracted. Yet objective observers with stop-watches can show that they are not nearly as fast as they think they are. PC's users tend try to use keyboard shortcuts more than Mac users - and that may actually harm their productivity.


So users often feel that one machine is faster, when it is not. In fact many studies have shown that Mac users are more productive and get work done faster than PC users, and with fewer errors -- all given the same level of expertise. This means that Macs are faster in areas where it counts (making YOU productive) - but PC's are sometimes better at creating illusion of speed while harming productivity with those same features. Apple's UI engineers have always been looking for what is better and more productive and smoother - even if users will notice the Macs speed less.

Once again, I agree with Apple's approach to user interface. In an interface I want "better to use", not flimflam or illusions that cost me precious time and productivity.

Created: 02/15/97
Updated: 11/09/02

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