Algo lags in the noon than in the morning

You don't say what instance type you're using. If you're using a T-series instance you should be aware that the CPU performance consumes "credits" and when they run out the performance may not be appropriate for your application. See our documentation for more information.

How can you fix this? You can use a larger instance type (which has more credits); you can launch the instance in "Unlimited" mode where you will be charged if (and only if) you run out of credits - but performance will not be impacted; or you can use a different instance type.