Postgres process count GCC vs Clang is Different on autovaccum=on

[hpc researcher_mspk <hpcresearch.mspk@xxxxxxxxx>]

Software/Hardware used:

===================

PostgresV14.v
OS: RHELv8.4
Benchmark:HammerDB v4.3
Hardware used: Apple/AMD Ryzen.
RAM size: 256 GB
SSD/HDD: 1TB
CPU(s): 256(0-255)
Thread(s) per core:  2
Core(s) per socket:  64
Socket(s):           2
NUMA node(s):        8

Command used to count process: ps -eaf | grep postgres

Case1: AutoVaccum=on

vu	GCC	Clang
32	43	42
64	76	74
192	203	202
250	262	262

Case2:AutoVaccum=off

vu	GCC	Clang
32	40	40
64	72	72
192	200	200
250	261	263

In Case1 why is the process different in Clang vs GCC.
In postgresql process dependent wrt compiler GCC/Clang?
Is any recommendation or suggestion to check on this in Postgresv14