Windows application performance deteriorates in EC2 instance created by custom AMI

I have created a Windows custom AMI with some custom Windows application.I use this AMI to generate EC2 instances.

I have run into a strange issue:

• All the applications run smoothly in the EC2 instance created from the custom AMI.
• However, after 24 hours, when I created an EC2 instance using the same custom image, the performance of the applications deteriorate.
• Even opening an application on the EC2 instance is much slower compared to the EC2 instance which was created 24 hours prior.

Any Suggestions would be really helpful.