CSGO drops FPS everytime someone connects to the server

Tested on official deathmatch servers.

FULL PC Specification:
GPU - MSI Nvidia GeForce GTX 970 4GB
CPU - Intel i5-8500 @ 3.00 GHz - Turbo 4.10 GHz
RAM - Corsair Vengeance LPX 2x8GB DDR4 (2400MHz) Black
SSD - KIOXIA EXCERIA 480GB
HDD - Seagate Barracuda 7200.12 SATA 750GB & HP 7200 SATA 500GB
PSU - Cooler Master MWE 500
Motherboard - MSI H310M PRO-VDH PLUS
CPU Fan - Cooler Master Hyper T200