🐛 Bug Report

When compared to running Selenium v.3.141.59 in hub and node setup, Selenium 4 beta consumes considerably more memory.

Usually when running Selenium 3.141.59 I would have 1 hub and 2 nodes - one with usually 5 threads running through xvfb and another 1 with 1 thread for confirming scenario's. The hub would rarely exceed 500mb memory usage, and the node running 5 threads rarely exceeded 1.5 gb after running for a few days.

After running overnight (~16 hours), Selenium 4 beta hub is consuming 4gb and the node is using 3.4gb (capability of 8 threads, but only 1 running) (note I also had a Firefox tab pointing to the server page (<server_url>:/ui/index.html#/)

To Reproduce

Detailed steps to reproduce the behavior:
Run a large suite overnight.
Moodle (moodle.org) is a large open source project that has a large suite that could be used (although this is not what I tested with, and may need some modifications to get to work with Selenium 4)

Expected behavior

RAM Usage for hub and node should be under 2 gb

Test script or set of commands reproducing this issue

Run a large suite

Environment

OS: Ubuntu 20.04 LTS
Browser: chrome
Browser version: 91.0.4472.77 (Official Build) (64-bit)
Browser Driver version: ChromeDriver 90
Language Bindings version: PHP
Selenium Grid version (if applicable): 4 beta 3

Java Version:
openjdk 11.0.11 2021-04-20
OpenJDK Runtime Environment (build 11.0.11+9-Ubuntu-0ubuntu2.20.04)
OpenJDK 64-Bit Server VM (build 11.0.11+9-Ubuntu-0ubuntu2.20.04, mixed mode, sharing)