Is there any performance benefit to running PAS on the same machine as DB and using shared memory?

[ChadThomsonPSC]

"is there any performance benefit if the PASOE is on the same machine as DB and the connection is done via shared memory?"

[ChadThomsonPSC]

The question is interpretted as: "Is there any performance benefit running PAS on same machine using shared memory, versus remote and TCP connection"?

Versions prior to v12 may see performance improvement by connecting via shared memory. However, local TCP connections (on some OSes) are actually shared-memory under-the-hood.

Depending on the deployment landscape, you may benefit overall from implementing TCP connections vs shared memory.
The v12 OpenEdge database server has seen dramatic performance improvments over previous releases, especially for remote connections.
Adopting a remote-connection style in your PAS configuration model up-front serves to prepare you for load-balancing, deployment to the cloud, and containerization strategies.