I am running the Magento 2.2.3 version on AWS EC2 currently on c5x.large the performance seems fine for me with proper page speed backed by CloudFront and Redis.
Due to cost optimization, I have decided to use the m4.large instance and saw the degradation in performance Magento page speed from 2.5 seconds to 6.6 seconds. I noticed the CPU usage with m4 large type instance it was going up during cache creation and was neutral at other time. I also noticed the cache flush operation from the Magento admin panel which took approx 3.5 min whereas in the case of C5 large it was taking 50 seconds to complete the same operation.
Is something wrong with my application or it's the cache operation that has a direct connection with my CPU? What will be the right Instance series to be chosen for Magento 2.2.3 on production?
Also, this was not the case with Magento 2.1.6, the cache flush operations are very normal even with t2.medium instances we used t2.medium for dev instances earlier.
Specifications: M4 large : 2 vcpu 8 GB RAM C5 Xlarge : 4 vcpu 8 GB RAM