MongoDB: Queries running twice slow on NEW server compared to OLD server

Question

I transferred current/old running DB into a new standalone server for MongoDB. To do this, I performed the following:

1. Took dump of data from OLD server
2. Restored data from the generated dump into NEW server
3. Configured the server for authentication

Issue:
I noticed that after performing the above, few queries on the NEW server were running slow almost twice the time compared to their performance on the OLD server.

Configurations:
The configurations of both the servers are same however the NEW server has 32 GB RAM while the OLD server had 28GB RAM. OLD server had other applications and servers running as well. While the NEW server is a dedicated server only for this DB.

CPU consumption is similar however RAM is heavily occupied in the OLD server while it is comparatively less occupied on NEW server.

Therefore, NEW server is better equipped in hardware and RAM consumption. Also NEW server is standalone dedicated to only this DB.

Question:
Why could my NEW server even though it is standalone be slow compared to OLD one? How can I correct this?

Answer 1

I noticed that the server wasn't set to NUMA as interleaved (disabled). Once I did it on the new server, the database started to pickup speed now. But still almost same as OLD server not better.