I was contemplating including the information above, but you figured it out anyway. :)
The reason is I HAVE to connect my monitor to my mobo hdmi to get reverse prime to work (otherwise everything would run on the nvidia rather than on my CPU, xrandr doesn’t want to move the ouput on this machine for some reason, neither on x11 nor on wayland)
What I could do to further test this is to connect my monitor to the nvidia and retry and see if it still throttles. Maybe there is a limit how much it can consume while having to “reroute” the signal to my mobo hdmi…
Edit
So @generix I connected the monitor to a port on the GPU, ran the debug tool, started a demanding game and debug one more time:
nvidia-bug-report-nv_hdmi.log.gz (924.7 KB)
nvidia-bug-report-nv_hdmi-game.log.gz (958.9 KB)
I had to go x11 since wayland bugged out completely, visual bugs everywhere, flickering in steam and game freezing on load. :-/
I added fan speed in mangohud yesterday, and it seems to work fine when in reverse prime, usually running at 65-85% when gaming.
But look at this when I used the GPU hdmi!

Something fishy is going on here.
Could be mangohud though, idk.
Maybe you see something more in the logs?
Edit 2
Maybe this information could be useful:
inxi -Fazy
System:
Kernel: 6.8.5-arch1-1 arch: x86_64 bits: 64 compiler: gcc v: 13.2.1
clocksource: tsc avail: hpet,acpi_pm parameters: BOOT_IMAGE=/vmlinuz-linux
root=UUID=78235068-f1ca-4363-99b1-474175fb3438 rw rootflags=subvol=@
zswap.enabled=0 rootfstype=btrfs modeset=1 sysrq_always_enabled=1 fbdev=1
nvidia_drm.modeset=1 loglevel=3 amd-pstate=guided
Desktop: KDE Plasma v: 6.0.3 tk: Qt v: N/A info: frameworks v: 6.1.0
wm: kwin_wayland vt: 2 dm: SDDM Distro: Arch Linux
Machine:
Type: Desktop Mobo: Gigabyte model: X670 AORUS ELITE AX v: x.x
serial: <superuser required> uuid: <superuser required> UEFI: American
Megatrends LLC. v: F22 date: 03/11/2024
CPU:
Info: model: AMD Ryzen 9 7900X bits: 64 type: MT MCP arch: Zen 4 gen: 5
level: v4 note: check built: 2022+ process: TSMC n5 (5nm) family: 0x19 (25)
model-id: 0x61 (97) stepping: 2 microcode: 0xA601206
Topology: cpus: 1x cores: 12 tpc: 2 threads: 24 smt: enabled cache:
L1: 768 KiB desc: d-12x32 KiB; i-12x32 KiB L2: 12 MiB desc: 12x1024 KiB
L3: 64 MiB desc: 2x32 MiB
Speed (MHz): avg: 3304 high: 5402 min/max: 400/5733 boost: enabled scaling:
driver: amd-pstate governor: schedutil cores: 1: 3005 2: 3005 3: 3005 4: 3005
5: 3005 6: 3005 7: 3005 8: 3855 9: 4110 10: 3005 11: 5402 12: 3005 13: 3005
14: 3005 15: 3372 16: 3005 17: 3005 18: 3005 19: 3039 20: 3005 21: 3121
22: 3005 23: 5328 24: 3005 bogomips: 225258
Flags: avx avx2 ht lm nx pae sse sse2 sse3 sse4_1 sse4_2 sse4a ssse3 svm
Vulnerabilities:
Type: gather_data_sampling status: Not affected
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: reg_file_data_sampling status: Not affected
Type: retbleed status: Not affected
Type: spec_rstack_overflow mitigation: Safe RET
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: Enhanced / Automatic IBRS; IBPB: conditional;
STIBP: always-on; RSB filling; PBRSB-eIBRS: Not affected; BHI: Not
affected
Type: srbds status: Not affected
Type: tsx_async_abort status: Not affected
Graphics:
Device-1: NVIDIA GA102 [GeForce RTX 3090] vendor: eVga.com. driver: nvidia
v: 550.67 alternate: nouveau,nvidia_drm non-free: 550.xx+ status: current
(as of 2024-04; EOL~2026-12-xx) arch: Ampere code: GAxxx
process: TSMC n7 (7nm) built: 2020-2023 pcie: gen: 1 speed: 2.5 GT/s
lanes: 16 link-max: gen: 4 speed: 16 GT/s ports: active: none empty: DP-1,
DP-2, DP-3, HDMI-A-1 bus-ID: 01:00.0 chip-ID: 10de:2204 class-ID: 0300
Device-2: AMD Raphael vendor: Gigabyte driver: amdgpu v: kernel
arch: RDNA-2 code: Navi-2x process: TSMC n7 (7nm) built: 2020-22 pcie: gen: 4
speed: 16 GT/s lanes: 16 ports: active: HDMI-A-2 empty: DP-4, DP-5, DP-6,
Writeback-1 bus-ID: 15:00.0 chip-ID: 1002:164e class-ID: 0300 temp: 52.0 C
Display: wayland server: X.org v: 1.21.1.13 with: Xwayland v: 23.2.6
compositor: kwin_wayland driver: X: loaded: modesetting,nvidia
alternate: fbdev,nouveau,nv,vesa dri: radeonsi gpu: nvidia,amdgpu
display-ID: 0
Monitor-1: HDMI-A-2 res: 1920x1080 size: N/A modes: N/A
API: EGL v: 1.5 hw: drv: nvidia drv: amd radeonsi platforms: device: 0
drv: nvidia device: 2 drv: radeonsi device: 3 drv: swrast gbm: drv: nvidia
surfaceless: drv: nvidia wayland: drv: radeonsi x11: drv: radeonsi
inactive: device-1
API: OpenGL v: 4.6.0 compat-v: 4.5 vendor: amd mesa v: 24.0.5-arch1.1
glx-v: 1.4 direct-render: yes renderer: AMD Radeon Graphics (radeonsi
raphael_mendocino LLVM 17.0.6 DRM 3.57 6.8.5-arch1-1) device-ID: 1002:164e
memory: 500 MiB unified: no display-ID: :0.0
API: Vulkan v: 1.3.279 layers: 7 device: 0 type: discrete-gpu
name: NVIDIA GeForce RTX 3090 driver: nvidia v: 550.67 device-ID: 10de:2204
surfaces: xcb,xlib,wayland
Audio:
Device-1: NVIDIA GA102 High Definition Audio vendor: eVga.com.
driver: snd_hda_intel v: kernel pcie: gen: 4 speed: 16 GT/s lanes: 16
bus-ID: 01:00.1 chip-ID: 10de:1aef class-ID: 0403
Device-2: AMD Rembrandt Radeon High Definition Audio driver: snd_hda_intel
v: kernel pcie: gen: 4 speed: 16 GT/s lanes: 16 bus-ID: 15:00.1
chip-ID: 1002:1640 class-ID: 0403
Device-3: AMD Family 17h/19h HD Audio vendor: Gigabyte
driver: snd_hda_intel v: kernel pcie: gen: 4 speed: 16 GT/s lanes: 16
bus-ID: 15:00.6 chip-ID: 1022:15e3 class-ID: 0403
API: ALSA v: k6.8.5-arch1-1 status: kernel-api tools: N/A
Server-1: JACK v: 1.9.22 status: off tools: N/A
Server-2: PipeWire v: 1.0.5 status: active with: 1: pipewire-pulse
status: active 2: wireplumber status: active tools: pactl,pw-cat,pw-cli,wpctl
Network:
Device-1: Realtek RTL8125 2.5GbE vendor: Gigabyte driver: r8169 v: kernel
pcie: gen: 2 speed: 5 GT/s lanes: 1 port: e000 bus-ID: 0e:00.0
chip-ID: 10ec:8125 class-ID: 0200
IF: enp14s0 state: up speed: 1000 Mbps duplex: full mac: <filter>
Device-2: MEDIATEK MT7922 802.11ax PCI Express Wireless Network Adapter
driver: mt7921e v: kernel pcie: gen: 2 speed: 5 GT/s lanes: 1 bus-ID: 0f:00.0
chip-ID: 14c3:0616 class-ID: 0280
IF: wlan0 state: down mac: <filter>
Info: services: NetworkManager,systemd-timesyncd
Bluetooth:
Device-1: MediaTek Wireless_Device driver: btusb v: 0.8 type: USB rev: 2.1
speed: 480 Mb/s lanes: 1 mode: 2.0 bus-ID: 3-7:3 chip-ID: 0e8d:0616
class-ID: e001 serial: <filter>
Report: rfkill ID: hci0 rfk-id: 0 state: down bt-service: disabled
rfk-block: hardware: no software: no address: see --recommends
Drives:
Local Storage: total: 6.08 TiB used: 1.97 TiB (32.4%)
SMART Message: Unable to run smartctl. Root privileges required.
ID-1: /dev/nvme0n1 maj-min: 259:3 vendor: Samsung model: SSD 980 PRO 1TB
size: 931.51 GiB block-size: physical: 512 B logical: 512 B speed: 63.2 Gb/s
lanes: 4 tech: SSD serial: <filter> fw-rev: 5B2QGXA7 temp: 46.9 C
scheme: GPT
ID-2: /dev/nvme1n1 maj-min: 259:0 vendor: Samsung model: SSD 990 PRO 2TB
size: 1.82 TiB block-size: physical: 512 B logical: 512 B speed: 63.2 Gb/s
lanes: 4 tech: SSD serial: <filter> fw-rev: 0B2QJXG7 temp: 43.9 C
scheme: GPT
ID-3: /dev/sda maj-min: 8:0 vendor: Samsung model: SSD 860 EVO 500GB
size: 465.76 GiB block-size: physical: 512 B logical: 512 B speed: 6.0 Gb/s
tech: SSD serial: <filter> fw-rev: 4B6Q scheme: GPT
ID-4: /dev/sdb maj-min: 8:16 vendor: Intel model: SSDSC2BF180A4H
size: 167.68 GiB block-size: physical: 512 B logical: 512 B speed: 6.0 Gb/s
tech: SSD serial: <filter> fw-rev: LH6i scheme: GPT
ID-5: /dev/sdc maj-min: 8:32 vendor: Western Digital
model: WD30EFRX-68EUZN0 size: 2.73 TiB block-size: physical: 4096 B
logical: 512 B speed: 6.0 Gb/s tech: HDD rpm: 5400 serial: <filter>
fw-rev: 0A80 scheme: GPT
Partition:
ID-1: / raw-size: 100 GiB size: 100 GiB (100.00%) used: 17.85 GiB (17.8%)
fs: btrfs dev: /dev/sda2 maj-min: 8:2
ID-2: /boot raw-size: 512 MiB size: 511 MiB (99.80%)
used: 241.2 MiB (47.2%) fs: vfat dev: /dev/sda1 maj-min: 8:1
ID-3: /home raw-size: 301.26 GiB size: 301.26 GiB (100.00%)
used: 137.25 GiB (45.6%) fs: btrfs dev: /dev/sda3 maj-min: 8:3
ID-4: /var/log raw-size: 100 GiB size: 100 GiB (100.00%)
used: 17.85 GiB (17.8%) fs: btrfs dev: /dev/sda2 maj-min: 8:2
Swap:
Kernel: swappiness: 60 (default) cache-pressure: 100 (default) zswap: no
ID-1: swap-1 type: zram size: 10.17 GiB used: 0 KiB (0.0%) priority: 100
comp: zstd avail: lzo,lzo-rle,lz4,lz4hc,842 max-streams: 24 dev: /dev/zram0
Sensors:
System Temperatures: cpu: 58.8 C mobo: 46.0 C gpu: amdgpu temp: 53.0 C
Fan Speeds (rpm): N/A
Info:
Memory: total: 32 GiB note: est. available: 30.5 GiB used: 2.79 GiB (9.2%)
Processes: 442 Power: uptime: 16m states: freeze,mem,disk suspend: deep
avail: s2idle wakeups: 0 hibernate: platform avail: shutdown, reboot,
suspend, test_resume image: 12.16 GiB services: org_kde_powerdevil,upowerd
Init: systemd v: 255 default: graphical tool: systemctl
Packages: pm: pacman pkgs: 1046 libs: 323 tools: yay pm: flatpak pkgs: 0
Compilers: gcc: 13.2.1 Shell: Zsh v: 5.9 default: Bash v: 5.2.26
running-in: yakuake inxi: 3.3.34