Performance indicators
Performance indicators
Here are a few performance indicators we can use to measure the performance:
CPU Benchmark Score
This is the score of the CPU posted on https://www.cpubenchmark.net/. Note that the posted scores are averages and may vary daily. Higher is better.
Minimum Keystroke Delay
This is the minimum time, in milliseconds, that the user needs to wait between keystrokes to avoid visible lag and missed keystrokes. Lower is better.
Methodology
This value is measured in a lab environment using a tool built into the POS software.
The input keystrokes and the POS' output are compared, and the delay is shortened until one of two things happen:
The POS starts "missing" keystrokes. (i.e. a key is pressed but the POS fails to register it), or;
There is visible lag, meaning there is a significant and clearly visible delay between the keystroke and the information appearing on the screen.
The delay between keystrokes is then increased gradually until the POS can reliably process all keystrokes without missing one and without creating significant lag, for a period of at least one full minute.
Maximum keys / second
This is the maximum theoretical number of keystrokes per second that a user can achieve without causing the POS to lag. Higher is better.
Methodology
This value is calculated from the minimum keystroke delay. For example, with a minimum keystroke delay of 100 milliseconds, we can have a theoretical maximum of 10 keystrokes per second.
Maximum keys / minute
This is the maximum theoretical number of keystrokes per minute that a user can achieve without causing the POS to lag. Higher is better.
Methodology
This figure is obtained by multiplying Max Keys / Second by 60. This figure is used to put the keystroke delay and keys per second values in perspective. Knowing that an average typist can do between 190 and 200 keystrokes per minute on a keyboard, while a "two-finger" typist does 150 to 160, this figure makes it easy to determine if the POS hardware will be able to keep up with the employees using it.
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