sound – Lag when watching a Streaming or during webRTC conference

I installed Ubuntu v 20.04 LTS, here is my config:

$ inxi -Fxz
  Kernel: 5.8.0-40-generic x86_64 bits: 64 compiler: N/A 
  Desktop: Gnome 3.36.4 Distro: Ubuntu 20.04.1 LTS (Focal Fossa) 
  Type: Laptop System: Dell product: Latitude E6540 v: 00 serial: <filter> 
  Mobo: Dell model: 0PXPYJ v: A00 serial: <filter> BIOS: Dell v: A24 
  date: 02/01/2018 
  ID-1: BAT0 charge: 79.4 Wh condition: 79.4/99.9 Wh (79%) 
  model: LGC-LGC3.0 DELL 5DN1K58 status: Charging 
  Topology: Dual Core model: Intel Core i7-4610M bits: 64 type: MT MCP 
  arch: Haswell rev: 3 L2 cache: 4096 KiB 
  flags: avx avx2 lm nx pae sse sse2 sse3 sse4_1 sse4_2 ssse3 vmx 
  bogomips: 23946 
  Speed: 812 MHz min/max: 800/3700 MHz Core speeds (MHz): 1: 967 2: 1014 
  3: 992 4: 982 
  Device-1: Intel 4th Gen Core Processor Integrated Graphics vendor: Dell 
  driver: i915 v: kernel bus ID: 00:02.0 
  Device-2: AMD Mars XTX (Radeon HD 8790M) vendor: Dell driver: amdgpu 
  v: kernel bus ID: 01:00.0 
  Display: x11 server: X.Org 1.20.9 driver: amdgpu 
  resolution: 1920x1080~60Hz, 1920x1080~60Hz, 1920x1080~60Hz 
  OpenGL: renderer: Mesa DRI Intel HD Graphics 4600 (HSW GT2) 
  v: 4.5 Mesa 21.1.0-devel (git-96d7555 2021-01-22 focal-oibaf-ppa) 
  direct render: Yes 
  Device-1: Intel Xeon E3-1200 v3/4th Gen Core Processor HD Audio 
  vendor: Dell driver: snd_hda_intel v: kernel bus ID: 00:03.0 
  Device-2: Intel 8 Series/C220 Series High Definition Audio vendor: Dell 
  driver: snd_hda_intel v: kernel bus ID: 00:1b.0 
  Sound Server: ALSA v: k5.8.0-40-generic 
  Device-1: Intel Ethernet I217-LM vendor: Dell driver: e1000e v: 3.2.6-k 
  port: f080 bus ID: 00:19.0 
  IF: eno1 state: down mac: <filter> 
  Device-2: Intel Centrino Advanced-N 6235 driver: iwlwifi v: kernel 
  port: e000 bus ID: 03:00.0 
  IF: wlp3s0 state: up mac: <filter> 
  Local Storage: total: 238.47 GiB used: 134.44 GiB (56.4%) 
  ID-1: /dev/sda vendor: SanDisk model: X300 2.5 7MM 256GB size: 238.47 GiB 
  Hardware-1: Intel 82801 Mobile SATA Controller (RAID mode) driver: ahci 
  v: 3.0 bus ID: 00:1f.2 
  ID-1: / size: 233.24 GiB used: 134.44 GiB (57.6%) fs: ext4 dev: /dev/sda5 
  System Temperatures: cpu: 57.0 C mobo: 57.0 C sodimm: 37.0 C gpu: amdgpu 
  temp: 53 C 
  Fan Speeds (RPM): cpu: 3992 
  Processes: 275 Uptime: 14h 00m Memory: 15.55 GiB used: 1.98 GiB (12.7%) 
  Init: systemd runlevel: 5 Compilers: gcc: 9.3.0 Shell: bash v: 5.0.17 
  inxi: 3.0.38 

As soon as I participate in a web browser based conference with another participant, or that I watch a Twitch channel, the OS starts to lag to the point where each action takes 30 seconds to be executed, in other words that I can no longer do anything . During the video, the other participant sees me frozen, and hears me badly. I have no issue while whatching youtube videos.

Do you have any advice for me?
I updated the graphics card driver, but nothing helps.

FYI, I had windows 7 on this machine before that, and I had no problem with streaming or videoconferencing.