Recently I was doing some small testing by using EC2 instances on
AWS and I noticed the execution time and performance highly
depend on which time of the day I am running my scripts. I was
t3.xlarge instance type as I didn’t need many
CPUs and memory for my tests, but from time to time I planned to
use all the resources for a short time (few minutes), and this is
when I noticed the difference.
First, let’s see what AWS says about
T3 instances start in Unlimited mode by default, giving users the
ability to sustain high CPU performance over any desired time
frame while keeping cost as low as possible.
In theory, I should not have any issues or performance
differences. I have also monitored the CPU credit balance and
there was no correlation between the balance and the performance
at all, and because these were unlimited instances the balance
should not have any impact.