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How fast should my spreadsheet calculate?
Studies on the effects of slow response time (see below) show that there are two ‘comfort zones’ of calculation times for users:
For calculation times of less than about a tenth of a second users feel comfortable with Automatic Calculation.
For calculation times of up to about 10 seconds in Manual Calculation mode users can maintain concentration and avoid errors.
So wherever possible you should try to use FastExcel to get your workbook calculation speed into one of these comfort zones.
The Effects of Slow Response Time
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Research studies show that a user’s productivity and ability to focus on the task deteriorate as response time lengthens.
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Response time greater than 10 seconds:
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Users generally refuse to wait longer than 10 seconds
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When response time is longer than 10 seconds users tend to switch to other tasks.
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Response time greater than 1 second but less than 10 seconds:
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User errors, and annoyance level, start to increase, particularly for repetitive tasks
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When response time is less than 10 seconds but longer than 1 second the user has difficulty in retaining a train of thought, but will probably not have switched to doing a different task whilst they are waiting.
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Sub-Second Response:
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Improving calculation speed to less than a second increases productivity
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For response times greater than a tenth of a second but still less than about 1 second, users can successfully keep a train of thought going, although they will notice the response time delay. IBM studies from the 1970s and 1980s showed significant productivity gains for users when response times were less than a second.
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You will probably need to switch to Manual Calculation mode when entering data.
Instant response
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