Problem playing 4K video

I am having trouble playing 4K videos. Frame drops and what not.

inxi -Fza

System:
  Kernel: 6.1.25-1-lts arch: x86_64 bits: 64 compiler: gcc v: 12.2.1
    parameters: BOOT_IMAGE=/@/boot/vmlinuz-linux-lts
    root=UUID=fb42bd95-a99a-4656-aa80-ed98d6452ed6 rw rootflags=subvol=@
    nowatchdog nvme_load=YES loglevel=3
  Desktop: KDE Plasma v: 5.27.4 tk: Qt v: 5.15.9 wm: kwin_x11 vt: 1 dm: SDDM
    Distro: EndeavourOS base: Arch Linux
Machine:
  Type: Desktop Mobo: Micro-Star model: A520M-A PRO (MS-7C96) v: 1.0
    serial: <superuser required> UEFI: American Megatrends v: 1.10
    date: 09/09/2020
CPU:
  Info: model: AMD Ryzen 5 3500 bits: 64 type: MCP arch: Zen 2 gen: 3
    level: v3 note: check built: 2020-22 process: TSMC n7 (7nm)
    family: 0x17 (23) model-id: 0x71 (113) stepping: 0 microcode: 0x8701021
  Topology: cpus: 1x cores: 6 smt: <unsupported> cache: L1: 384 KiB
    desc: d-6x32 KiB; i-6x32 KiB L2: 3 MiB desc: 6x512 KiB L3: 16 MiB
    desc: 2x8 MiB
  Speed (MHz): avg: 2456 high: 3739 min/max: 2200/4120 boost: enabled
    scaling: driver: acpi-cpufreq governor: schedutil cores: 1: 3739 2: 2200
    3: 2200 4: 2200 5: 2199 6: 2200 bogomips: 43216
  Flags: avx avx2 ht lm nx pae sse sse2 sse3 sse4_1 sse4_2 sse4a ssse3 svm
  Vulnerabilities:
  Type: itlb_multihit status: Not affected
  Type: l1tf status: Not affected
  Type: mds status: Not affected
  Type: meltdown status: Not affected
  Type: mmio_stale_data status: Not affected
  Type: retbleed mitigation: untrained return thunk; SMT disabled
  Type: spec_store_bypass mitigation: Speculative Store Bypass disabled via
    prctl
  Type: spectre_v1 mitigation: usercopy/swapgs barriers and __user pointer
    sanitization
  Type: spectre_v2 mitigation: Retpolines, IBPB: conditional, STIBP:
    disabled, RSB filling, PBRSB-eIBRS: Not affected
  Type: srbds status: Not affected
  Type: tsx_async_abort status: Not affected
Graphics:
  Device-1: NVIDIA GK208B [GeForce GT 730] driver: nvidia v: 470.182.03
    alternate: nouveau,nvidia_drm non-free: series: 470.xx+
    status: legacy-active (EOL~2023/24) arch: Kepler code: GKxxx
    process: TSMC 28nm built: 2012-18 pcie: gen: 2 speed: 5 GT/s lanes: 8
    bus-ID: 25:00.0 chip-ID: 10de:1287 class-ID: 0300
  Display: x11 server: X.Org v: 21.1.8 compositor: kwin_x11 driver: X:
    loaded: nvidia unloaded: modesetting alternate: fbdev,nouveau,nv,vesa
    gpu: nvidia display-ID: :0 screens: 1
  Screen-1: 0 s-res: 1920x1080 s-dpi: 92 s-size: 530x301mm (20.87x11.85")
    s-diag: 610mm (24")
  Monitor-1: HDMI-0 res: 1920x1080 hz: 60 dpi: 92
    size: 528x297mm (20.79x11.69") diag: 606mm (23.85") modes: N/A
  API: OpenGL v: 4.6.0 NVIDIA 470.182.03 renderer: NVIDIA GeForce GT
    730/PCIe/SSE2 direct-render: Yes
Audio:
  Device-1: NVIDIA GK208 HDMI/DP Audio driver: snd_hda_intel v: kernel pcie:
    gen: 2 speed: 5 GT/s lanes: 8 bus-ID: 25:00.1 chip-ID: 10de:0e0f
    class-ID: 0403
  Device-2: AMD Starship/Matisse HD Audio vendor: Micro-Star MSI
    driver: snd_hda_intel v: kernel pcie: gen: 4 speed: 16 GT/s lanes: 16
    bus-ID: 27:00.4 chip-ID: 1022:1487 class-ID: 0403
  API: ALSA v: k6.1.25-1-lts status: kernel-api tools: alsamixer,amixer
  Server-1: PipeWire v: 0.3.69 status: active with: 1: pipewire-pulse
    status: active 2: wireplumber status: active 3: pipewire-alsa type: plugin
    4: pw-jack type: plugin tools: pactl,pw-cat,pw-cli,wpctl
Network:
  Device-1: Realtek RTL8111/8168/8411 PCI Express Gigabit Ethernet
    vendor: Micro-Star MSI driver: r8169 v: kernel pcie: gen: 1 speed: 2.5 GT/s
    lanes: 1 port: f000 bus-ID: 22:00.0 chip-ID: 10ec:8168 class-ID: 0200
  IF: enp34s0 state: up speed: 100 Mbps duplex: full mac: <filter>
Bluetooth:
  Device-1: TP-Link UB500 Adapter type: USB driver: btusb v: 0.8 bus-ID: 3-1:2
    chip-ID: 2357:0604 class-ID: e001 serial: <filter>
  Report: rfkill ID: hci0 rfk-id: 1 state: up address: see --recommends
Drives:
  Local Storage: total: 1.26 TiB used: 340.89 GiB (26.4%)
  SMART Message: Unable to run smartctl. Root privileges required.
  ID-1: /dev/nvme0n1 maj-min: 259:0 vendor: AARVEX model: 256GB SSD
    size: 238.47 GiB block-size: physical: 512 B logical: 512 B speed: 31.6 Gb/s
    lanes: 4 type: SSD serial: <filter> rev: V0808A0 temp: 43.9 C scheme: GPT
  ID-2: /dev/sda maj-min: 8:0 model: CONSISTENT SSD S6 128GB
    size: 119.24 GiB block-size: physical: 512 B logical: 512 B speed: 6.0 Gb/s
    type: SSD serial: <filter> rev: 8B0 scheme: GPT
  ID-3: /dev/sdb maj-min: 8:16 vendor: Western Digital
    model: WD10EZEX-00BBHA0 size: 931.51 GiB block-size: physical: 4096 B
    logical: 512 B speed: 6.0 Gb/s type: HDD rpm: 7200 serial: <filter>
    rev: 1A01 scheme: GPT
Partition:
  ID-1: / raw-size: 71.29 GiB size: 71.29 GiB (100.00%) used: 8.82 GiB (12.4%)
    fs: btrfs dev: /dev/nvme0n1p3 maj-min: 259:3
  ID-2: /boot/efi raw-size: 300 MiB size: 299.4 MiB (99.80%)
    used: 576 KiB (0.2%) fs: vfat dev: /dev/nvme0n1p1 maj-min: 259:1
  ID-3: /home raw-size: 166.88 GiB size: 166.88 GiB (100.00%)
    used: 3.07 GiB (1.8%) fs: btrfs dev: /dev/nvme0n1p2 maj-min: 259:2
  ID-4: /var/log raw-size: 71.29 GiB size: 71.29 GiB (100.00%)
    used: 8.82 GiB (12.4%) fs: btrfs dev: /dev/nvme0n1p3 maj-min: 259:3
Swap:
  Alert: No swap data was found.
Sensors:
  System Temperatures: cpu: 50.5 C mobo: N/A gpu: nvidia temp: 37 C
  Fan Speeds (RPM): N/A gpu: nvidia fan: 40%
Info:
  Processes: 261 Uptime: 2h 29m wakeups: 9 Memory: 15.54 GiB
  used: 3.04 GiB (19.5%) Init: systemd v: 253 default: graphical
  tool: systemctl Compilers: gcc: 12.2.1 Packages: pm: pacman pkgs: 1122
  libs: 328 tools: yay Shell: Bash v: 5.1.16 running-in: konsole inxi: 3.3.26

Where are you trying to play 4k video’s from? (ie Local computer or Internet/Streaming) What is the codec in use? what player / browser are you using to play from.

I shot some videos on my phone and they play well there. Upon transferring them to pc, it doesn’t play…

you may want to enable full compositing for the nvidia driver…
https://wiki.archlinux.org/title/NVIDIA/Troubleshooting#Avoid_screen_tearing
https://discovery.endeavouros.com/nvidia/nvidia-optional-enhancements-and-troubleshooting/2021/03/

Is hardware acceleration enabled? See here for verification.

For NVIDIA you may need to use this.

My money is on the dated GPU. The CPU should be decent enough to compensate though, but in the end it’s hard to tell without knowing the actual video content. Do you have a sample video? What playback software do you use? Do you observe severe CPU usage?

From the specs it sounds that your hardware should be able to decode 4k with noticeable load, but it isn’t guaranteed.