Howdy,
Minor annoyance, nothing major, but it bugs me so I’m wondering if there is some setting I can adjust to fix it. 
I’m also comparing this performance to my previous Slackware installation.
The issue:
When running a video player, VLC/MPlayer/YouTube in a browser, and I open another app the video will stutter. Audio remains smooth, just the video becomes a slide show until the app finishes displaying its main screen. Also, when hovering the mouse over a video player in the task bar, the popup preview is like a slideshow.
On my Slackware box, with the same Desktop manager/kernel (listed below) I once had 6 VLC videos and a YouTube playing just to see if it I could, and they all played smoothly. Also, the previews in the taskbar were smooth playing as well.
Know of something I can try to prevent the video stuttering?
System info:
I’m running the KDE version of Manjaro, KDE 20.0.3 (minimal) with no personal kernel tweaks.
[Station1 ~]# inxi -F
System: Host: Station1 Kernel: 5.7.19-2-MANJARO x86_64 bits: 64 Console: tty 1 Distro: Manjaro Linux
Machine: Type: Desktop Mobo: Micro-Star model: Z370 GAMING PLUS (MS-7B61) v: 1.0 serial: I516394836
UEFI [Legacy]: American Megatrends v: 1.30 date: 03/07/2018
CPU: Topology: 6-Core model: Intel Core i7-8700 bits: 64 type: MT MCP L2 cache: 12.0 MiB
Speed: 800 MHz min/max: 800/4600 MHz Core speeds (MHz): 1: 800 2: 800 3: 800 4: 800 5: 800 6: 800 7: 800 8: 800
9: 800 10: 800 11: 800 12: 800
Graphics: Device-1: NVIDIA GM204 [GeForce GTX 970] driver: nvidia v: 450.66
Display: server: X.org 1.20.8 driver: nvidia tty: 157x40
Message: Advanced graphics data unavailable in console for root.
Audio: Device-1: Intel 200 Series PCH HD Audio driver: snd_hda_intel
Device-2: NVIDIA GM204 High Definition Audio driver: snd_hda_intel
Sound Server: ALSA v: k5.7.19-2-MANJARO
Network: Device-1: Intel Ethernet I219-V driver: e1000e
IF: enp0s31f6 state: up speed: 1000 Mbps duplex: full mac: 30:9c:23:cf:27:2e
Drives: Local Storage: total: 3.92 TiB used: 824.87 GiB (20.5%)
ID-1: /dev/sda vendor: Intel model: SSDSC2BB800G4 size: 745.21 GiB
ID-2: /dev/sdb vendor: Crucial model: CT1000MX500SSD1 size: 931.51 GiB
ID-3: /dev/sdc vendor: Western Digital model: WD20EZRZ-00Z5HB0 size: 1.82 TiB
ID-4: /dev/sdd vendor: A-Data model: SU800 size: 476.94 GiB
Partition: ID-1: / size: 468.45 GiB used: 11.05 GiB (2.4%) fs: ext4 dev: /dev/sdd1
ID-2: /home size: 491.15 GiB used: 47.40 GiB (9.7%) fs: ext4 dev: /dev/sdb1
Swap: Alert: No Swap data was found.
Sensors: System Temperatures: cpu: 27.0 C mobo: N/A
Fan Speeds (RPM): N/A
Info: Processes: 282 Uptime: 1h 45m Memory: 31.33 GiB used: 3.14 GiB (10.0%) Init: systemd Shell: Bash inxi: 3.1.05
Device/Screen/Extension sections of /etc/X11/mhwd.d/nvidia.conf:
Section "Device"
Identifier "Device0"
Driver "nvidia"
VendorName "NVIDIA Corporation"
Option "NoLogo" "1"
Option "Triplebuffer" "On"
Option "ConnectedToAcpid" "Off"
EndSection
Section "Screen"
Identifier "Screen0"
Device "Device0"
Monitor "Monitor0"
DefaultDepth 24
SubSection "Display"
Depth 24
EndSubSection
EndSection
Section "Extensions"
Option "COMPOSITE" "Enable"
EndSection