amd-bc250-docs/docs/troubleshooting/performance.md

Performance Troubleshooting

This guide covers common performance issues and their solutions for the BC-250.

---

Quick Diagnostics

Before troubleshooting specific issues, run these commands to check your system status:

# Check GPU frequency and temperature
sensors

# Check GPU clock state (live)
# Pick the right card: ls -l /sys/class/drm/ | grep card  (usually card0 for the BC-250)
watch -n 1 cat /sys/class/drm/card0/device/pp_dpm_sclk
watch -n 1 cat /sys/class/drm/card0/device/pp_dpm_mclk

# Note: `gpu_busy_percent` does NOT work on the BC-250 (amdgpu driver leaves
# the metric field uninitialised, hence the famous MangoHud 655% bug).
# See the MangoHud admonition further down for the fix and root cause.

# Check if GPU driver is loaded
lspci -k | grep -A 3 VGA

# Verify Mesa version
glxinfo | grep "OpenGL version"

# Check governor status
systemctl status cyan-skillfish-governor-smu
# or if using TT governor:
# systemctl status cyan-skillfish-governor-tt

---

GPU Locked at 1500MHz

Symptoms:

• GPU frequency stuck at 1500MHz regardless of load
• Low FPS in games despite acceptable temperatures
• radeontop or monitoring tools show constant 1500MHz

Cause: The default GPU governor is locked by BIOS. Without a user-space governor, the GPU cannot scale frequency dynamically.

Solution: Install GPU Governor

The BC-250 requires a custom GPU governor to enable dynamic frequency scaling between 350-2300MHz (patched kernel) or 1000-2000MHz (unpatched kernel).

Option 1: Cyan Skillfish Governor SMU (Recommended)

Features:

• Continuous frequency adjustment via SMU firmware calls
• Maintains GPU utilization 70-95% (configurable)
• No kernel patch required on any distro
• 24ms burst-to-max time
• More responsive to burst loads

Installation:

Fedora/RPM:

dnf copr enable filippor/bazzite
dnf install cyan-skillfish-governor-smu

Arch/AUR:

yay -S cyan-skillfish-governor-smu

Debian/Ubuntu: Upstream does not ship a .deb. Grab the latest cyan-skillfish-governor-smu-*-x86_64-linux.tar.gz from filippor's releases, extract it, and run sudo ./scripts/install.sh.

Configuration:

The governor uses voltage/frequency pairs. Edit the config file and add as many stable points as you've tested:

safe-points = [
    { freq_mhz = 350,  voltage_mv = 570 },
    { freq_mhz = 860,  voltage_mv = 600 },
    { freq_mhz = 1090, voltage_mv = 650 },
    { freq_mhz = 1280, voltage_mv = 700 },
    { freq_mhz = 1460, voltage_mv = 750 },
    { freq_mhz = 1620, voltage_mv = 800 },
    { freq_mhz = 1760, voltage_mv = 850 },
    { freq_mhz = 1890, voltage_mv = 900 },
    { freq_mhz = 2030, voltage_mv = 950 },
    { freq_mhz = 2090, voltage_mv = 975 },
    { freq_mhz = 2140, voltage_mv = 1000 },
    { freq_mhz = 2230, voltage_mv = 1050 },
]

load_target = { min = 70, max = 95 }

!!! warning "Test Your Values" Default values are conservative. Test stability for your specific board:

```bash
# Stop the governor
sudo systemctl stop cyan-skillfish-governor-smu

# Manually set frequency/voltage
echo vc 0 <CLOCK> <VOLTAGE> > /sys/devices/pci0000:00/0000:00:08.1/0000:01:00.0/pp_od_clk_voltage

# Run stress test (benchmark, game, etc.)
# If stable, add to config. If crashes, increase voltage or lower frequency.
```

Enable and start:

sudo systemctl enable --now cyan-skillfish-governor-smu

---

GPU Frequency Not Scaling Above 2000MHz

Symptoms:

• Governor installed but GPU won't go above 2000MHz
• Governor config shows max 2300MHz but actual frequency limited

Cause: Kernel doesn't have the frequency range patch.

Solution: Apply Kernel Patch

The BC-250 needs a kernel patch to unlock frequency range from 500-2500MHz (default is 1000-2000MHz).

Pre-patched Kernels:

Bazzite: Uses patched kernel by default (no action needed)

CachyOS:

# CachyOS has pre-patched kernels in their repo
paru -S linux-cachyos-lts-headers

Fedora/Arch - Manual Patch:

Download the patch:

wget https://raw.githubusercontent.com/mothenjoyer69/bc250-documentation/main/kernel-patches/amdgpu-frequency-range.patch

Apply to kernel source and recompile, or use a tool like dkms or CachyOS kernel manager.

Verification:

cat /sys/class/drm/card0/device/pp_od_clk_voltage
# Should show range up to 2300MHz or higher

---

Software Rendering (llvmpipe) Instead of GPU

Symptoms:

• glxinfo | grep "OpenGL renderer" shows "llvmpipe"
• Games extremely slow (5-10 FPS)
• Steam shows "Software Rendering" in system info

Diagnostic:

glxinfo | grep "OpenGL renderer"
# Bad:  OpenGL renderer string: llvmpipe (LLVM 15.0.0, 256 bits)
# Good: OpenGL renderer string: AMD Radeon Graphics (gfx1013, LLVM 15.0.0, DRM 3.54, 6.12.0)

vulkaninfo --summary
# Should show AMD RADV driver

Cause 1: Mesa Too Old

Solution: Upgrade to Mesa 25.1.3 or newer

Fedora 43+:

# Mesa 25.1+ is in official repos
sudo dnf update mesa*

!!!warning "Fedora 42 is End of Life" Upgrade to Fedora 43 which ships Mesa 25.x in repos.

Arch/Manjaro:

# Install from official repos
sudo pacman -S mesa

Verification:

glxinfo | grep "OpenGL version"
# Should show Mesa 25.1.3 or higher

Cause 2: Wrong Graphics Adapter Selected

Some games (especially Red Dead Redemption 2) default to software rendering.

Solution:

Check available adapters:

vulkaninfo --summary

In-game, change graphics adapter number to match the GPU (not llvmpipe).

For RDR2 specifically, launch with:

-useMaximumSettings

Cause 3: Driver Not Loaded

Check if amdgpu driver is loaded:

lspci -k | grep -A 3 VGA
# Should show "Kernel driver in use: amdgpu"

If not loaded, check:

dmesg | grep amdgpu
# Look for errors

Common fix - ensure these kernel parameters are set (and nomodeset is removed):

# Edit /etc/default/grub (sg_display=0 only needed for kernels < 6.10)
GRUB_CMDLINE_LINUX_DEFAULT="amdgpu.sg_display=0"

# Regenerate grub config
sudo grub2-mkconfig -o /boot/grub2/grub.cfg  # Fedora
sudo grub-mkconfig -o /boot/grub/grub.cfg    # Arch

---

Low FPS / Poor Gaming Performance

Check GPU Utilization

# Monitor GPU clock state under load (proxy for utilisation since gpu_busy_percent is broken on BC-250)
watch -n 1 cat /sys/class/drm/card0/device/pp_dpm_sclk

# If the * marker sits at the lowest level under a heavy game = governor not boosting
# If it sits at the top level = GPU is loaded; check temps and thermal throttle
# Alternative: `radeontop` for a busier overview (apt/dnf/pacman install radeontop)

Issue: Governor Not Installed

See "GPU Locked at 1500MHz" section above.

Issue: Broken Kernel Version

Symptoms:

• Previously working setup suddenly has poor performance after kernel update
• Random GPU crashes under load
• System freezes during gaming
• Running kernel 6.15.0-6.15.6 or 6.17.8-6.17.10

Solution:

Install Working Kernel

!!! danger "AVOID BROKEN KERNEL VERSIONS" Kernel 6.15.0-6.15.6 and 6.17.8-6.17.10 break GPU driver support. Use 6.18.18 LTS (recommended) or 6.17.11+ for best performance.

Arch/Manjaro:

# Option 1: Install working kernel (6.17.11+ or 6.18.x)
sudo pacman -S linux  # Check version is 6.17.11+ or 6.18.x
# Option 2: Install LTS kernel for guaranteed stability
sudo pacman -S linux-lts linux-lts-headers
# Set as default in bootloader

CachyOS:

# Check version first
paru -S linux-cachyos  # Ensure it's 6.17.11+ or 6.18.x
# Or for LTS stability:
paru -S linux-cachyos-lts linux-cachyos-lts-headers

Fedora:

# Check current kernel
uname -r

# Install older kernel from koji if needed
# Or wait for kernel fixes

Issue: IOMMU Causing Crashes

Symptoms:

• Random system crashes under GPU load
• Weird performance issues
• System hangs

!!! danger "IOMMU is Broken on BC-250" IOMMU MUST be disabled in BIOS. It is broken on BC-250 and causes crashes, display failures, and instability.

Solution:

Disable IOMMU in BIOS (required), or add kernel parameter as backup:

amd_iommu=off

Issue: Game-Specific Optimizations

Steam Launch Options:

# FSR enabled
WINE_FULLSCREEN_FSR=1 %command%

# Vulkan backend
PROTON_USE_WINED3D=0 %command%

# Gamescope for consistent frametimes
gamescope -W 1920 -H 1080 -f -- %command%

---

Thermal Throttling

Symptoms:

• Performance starts good then degrades after 5-15 minutes
• Temperatures above 85-90C
• GPU frequency drops under sustained load

Check Temperatures:

watch -n 1 sensors

Safe operating temperatures:

• 70-85C: Normal under load
• 85-90C: High but acceptable
• 90C+: Thermal throttling likely

Solutions:

1. Improve Cooling

Arctic P12 Max recommended (high static pressure: 3.27 mmH2O)

Alternative good options:

• Noctua NF-A12x25 (2.34 mmH2O)
• Arctic P14 PWM (2.4 mmH2O)

Fan configuration:

# Set fans to full speed in BIOS (for testing)
# Or use fan control software

2. Repaste / Replace Thermal Pads

• APU die: Use quality thermal paste (Arctic MX-4, Noctua NT-H1) or PTM7950 phase-change pad
• Memory/VRM: 2mm thermal pads (verify thickness first)
• Ensure heatsink is properly secured

3. Undervolt GPU

If thermal throttling persists, try undervolting:

# Example: 2000MHz at 940mV instead of 1000mV
echo vc 0 2000 940 > /sys/devices/pci0000:00/0000:00:08.1/0000:01:00.0/pp_od_clk_voltage
echo c > /sys/devices/pci0000:00/0000:00:08.1/0000:01:00.0/pp_od_clk_voltage

Test stability with benchmarks. If stable, update governor config.

---

VRAM Allocation Issues

Checking Current VRAM Split

# Total system RAM
free -h

# GPU VRAM visible
sudo lshw -C display | grep -i memory

Issue: Game Crashes with "Out of Memory"

Symptoms:

• Games crash after loading
• Artifacts then crash (Company of Heroes 3, RDR2)
• "Out of memory" errors

Common with: 512MB dynamic allocation + ZRAM enabled

Solution 1: Use Fixed VRAM Allocation

Boot into BIOS and change VRAM allocation:

• For most games: 4GB VRAM / 12GB RAM
• For competitive/esports: 6GB VRAM / 10GB RAM
• For VRAM-heavy games: 8GB VRAM / 8GB RAM or 10GB VRAM / 6GB RAM

!!! info "Dynamic Allocation Issues" 512MB dynamic allocation conflicts with ZRAM on some games. Use fixed allocation instead.

Solution 2: Disable ZRAM

# Disable ZRAM
sudo systemctl stop zram-swap
sudo systemctl disable zram-swap

Solution 3: Replace ZRAM with zswap (Better for RAM-Hungry Games)

zswap compresses swap in RAM before writing to disk, avoiding ZRAM's VRAM conflicts while still helping with memory pressure.

Bazzite setup:

# Disable zram
echo "" | sudo tee /etc/systemd/zram-generator.conf

# Set up swapfile first (see https://docs.bazzite.gg/Advanced/swapfile/)

# Enable lz4 drivers in initramfs
rpm-ostree initramfs --enable \
  --arg=--add-drivers \
  --arg=lz4 \
  --arg=--add-drivers \
  --arg=lz4_compress

# Add kernel parameters
rpm-ostree kargs --append-if-missing="zswap.enabled=1 zswap.max_pool_percent=25 zswap.compressor=lz4"

# Reboot, then set swappiness
echo 180 | sudo tee /proc/sys/vm/swappiness

Verify: grep -r . /sys/module/zswap/parameters/

!!!warning "zswap and SSD Wear" zswap eventually writes to your swap file on disk. Not recommended on slow storage devices.

Solution 4: Increase VRAM Visibility (Advanced)

For LLM/AI workloads that need more than 12GB VRAM:

Add to kernel command line:

amdgpu.gttsize=14750 ttm.pages_limit=3959290 ttm.page_pool_size=3959290

This allows GPU to allocate up to ~14.75GB VRAM. Limit usage to 14.25-14.5GB in applications to avoid crashes.

---

Stuttering and Frame Pacing

Issue: Inconsistent Frame Times

Symptoms:

• FPS counter shows 60+ but feels choppy
• Frame time graph shows spikes
• Stuttering during gameplay

Solution 1: Use Gamescope

Gamescope provides consistent frame pacing:

# Install gamescope
sudo dnf install gamescope  # Fedora
sudo pacman -S gamescope    # Arch

# Launch game through gamescope
gamescope -W 1920 -H 1080 -f -- %command%

# With frame limit
gamescope -W 1920 -H 1080 -r 60 -f -- %command%

Solution 2: Disable Compositor (X11)

For KDE Plasma (X11):

# Disable compositor in System Settings > Display > Compositor
# Or use keyboard shortcut: Alt+Shift+F12

Solution 3: Use Wayland

Wayland generally has better frame pacing than X11.

Solution 4: Audio Configuration

Some games (especially emulators) have frame pacing tied to audio:

# Check PulseAudio/PipeWire sample rate
pactl info | grep "Default Sample"

# Lock to 48kHz
# Edit /etc/pulse/daemon.conf (PulseAudio) or PipeWire config
default-sample-rate = 48000

For Ryujinx (Switch emulator): Change audio backend in settings can dramatically improve performance.

---

System Configuration Issues

Kernel Parameters (Optimal)

Edit /etc/default/grub:

GRUB_CMDLINE_LINUX_DEFAULT="amdgpu.sg_display=0 mitigations=off"

Explanation:

• amdgpu.sg_display=0: Required for kernel < 6.10 (doesn't hurt on newer)
• mitigations=off: +18 FPS in Cyberpunk 2077 (60→78 FPS) but reduces security

!!! danger "Security Warning" mitigations=off disables CPU vulnerability mitigations. Only use if you trust all code running on the system.

Regenerate grub:

sudo grub2-mkconfig -o /boot/grub2/grub.cfg  # Fedora
sudo grub-mkconfig -o /boot/grub/grub.cfg    # Arch

Remove nomodeset

!!! danger "Critical: Remove nomodeset After Driver Installation" nomodeset is ONLY for installation. It disables GPU acceleration. Remove it after Mesa is installed.

Check if present:

cat /etc/default/grub | grep nomodeset

If found, remove it and regenerate grub config.

---

Performance Monitoring Tools

Real-time Monitoring

MangoHud (in-game overlay):

# Install
sudo dnf install mangohud  # Fedora
sudo pacman -S mangohud    # Arch

# Use in Steam launch options
mangohud %command%

# Or global config in ~/.config/MangoHud/MangoHud.conf

!!! warning "MangoHud reports 655% GPU usage on BC-250"

The BC-250 `amdgpu` driver does not populate the GPU activity field of `/sys/.../gpu_metrics`. Bytes 0x1C-0x1D stay at `0xFFFF`, MangoHud reads that as 65535 and divides by 100, so the overlay shows **655%** GPU load. Reproduced on Fedora 43, kernel `7.0.9-105.fc43.x86_64`, MangoHud 0.8.2.

Fix: run `cyan-skillfish-governor-smu` (smu branch) with its defaults. The governor bind-mounts a writable tmpfs file over `gpu_metrics` and writes a sampled activity value (busy-flag method) into byte 0x1C every cycle. Anything that reads `gpu_metrics` (MangoHud, `radeontop`, etc.) then sees a sane percent. No MangoHud config change required.

```toml
# /etc/cyan-skillfish-governor-smu/config.toml — defaults shown for reference
[gpu-usage]
fix-metrics = true
method = "busy-flag"
flush-every = 10
```

Verified live: with the governor stopped, bytes at offset 0x1C of `gpu_metrics` read `ffff`. With the governor running, the same bytes read `0000` at idle (0%). Bind mount is visible in `/proc/self/mountinfo` while the service is active.

Source: [filippor/cyan-skillfish-governor `smu` branch — `src/gpu_usage_fix.rs`](https://github.com/filippor/cyan-skillfish-governor/blob/smu/src/gpu_usage_fix.rs).

Radeontop (terminal):

sudo dnf install radeontop
radeontop

Sensors (temperatures/voltages):

watch -n 1 sensors

CoolerControl (GUI):

# Fedora/Bazzite
ujust install-coolercontrol

# Provides fan control and sensor monitoring

Benchmarking

Unigine Superposition:

# Good for thermal/stability testing
# 1080p Extreme preset
# Stock BC-250: ~3888 score
# 2.22GHz OC: ~4118 score

vkmark (Vulkan):

sudo dnf install vkmark
vkmark

Cyberpunk 2077 Benchmark: Popular community test - consistent results:

• Stock: ~57 FPS (1080p high)
• 2.22GHz: ~60 FPS
• With mitigations=off: +15-20 FPS

Testing GPU Load on a Headless BC-250

A lot of BC-250 builds run headless (LLM server, render farm, etc). When you want to verify the GPU is actually being loaded by your workload, two pitfalls to avoid:

!!!warning "Don't use glmark2 --off-screen to test GPU load on a headless box" Without a display, glmark2 --off-screen silently falls back to LLVMpipe (CPU software rendering). The GPU does nothing, gpu_busy_percent stays at 0, the governor never boosts, and you may chase a phantom "governor doesn't work" bug for hours. This is documented experience from BC-250 maintainers.

Use one of these to load the GPU for real:

# Vulkan compute, deterministic
clpeak

# Real-world Vulkan workload
llama-bench -m model.gguf -ngl 99

# Vulkan rendering benchmark (offscreen works correctly)
vkmark

To confirm the GPU is genuinely loaded before drawing any conclusions from a test, check the GPU clock and power are actually climbing:

# In another terminal while your test runs
watch -n 1 cat /sys/kernel/debug/dri/0/amdgpu_pm_info 2>/dev/null \
    | grep -E "GFX|SCLK|MCLK|^[[:space:]]*[0-9]+\.[0-9]+ W"

If SCLK stays at idle and power stays under 60 W during your "load test", the test isn't loading the GPU and any conclusions you draw from it are noise.

---

Distribution-Specific Issues

Fedora

Issue: MTG Arena crashes GUI

• Confirmed issue on Fedora with Gnome
• Works fine on Manjaro
• Try KDE Plasma instead of Gnome

Bazzite

Issue: Freeze on Sleep

• Known issue: system appears frozen when entering sleep
• Solution: Press power button to wake (don't hold, just press)

Issue: Bazzite Update Breaks System

• If an update causes issues, rollback:

rpm-ostree status
rpm-ostree rollback

CachyOS

Issue: Installation ISO Won't Boot

• Use LTS kernel ISO
• Build custom ISO with LTS kernel (see guide in System Configuration section)

---

Quick Performance Checklist

Use this checklist to verify your system is properly configured:

• Mesa version 25.1.3 or higher
• Kernel 6.18.18 LTS (recommended), 6.17.11+, or 6.12.x-6.14.x LTS (NOT 6.15.0-6.15.6 or 6.17.8-6.17.10)
• GPU governor installed and running (cyan-skillfish-governor-smu recommended)
• nomodeset removed from kernel parameters
• BIOS flashed to P3.00 with 512MB dynamic or 4-12GB fixed VRAM
• glxinfo shows RADV driver, not llvmpipe
• Temperatures under 85C under load
• Cooling with high static pressure fan (>2.0 mmH2O)
• IOMMU disabled in BIOS
• systemctl status cyan-skillfish-governor-smu shows active

Quick test:

# This should show GPU scaling dynamically
watch -n 0.5 'cat /sys/class/drm/card0/device/pp_dpm_sclk && cat /sys/class/drm/card0/device/pp_dpm_mclk'

# Run a game or benchmark
# Frequency should scale from ~1000MHz idle to 2000+MHz under load
# GPU utilization should be 80-100% in demanding scenes

---

Getting Help

If you're still experiencing performance issues after following this guide:

1. Gather system information:

# Create a system report
uname -r                    # Kernel version
glxinfo | grep -i mesa      # Mesa version
sensors                     # Temperatures
systemctl status cyan-skillfish-governor-smu  # Governor status
dmesg | grep amdgpu | tail -50    # Recent GPU messages

2. Join the Discord community:

• BC-250 Discord: Largest community, most active support
• Search for your specific issue first - likely already solved

3. Check GitHub documentation:

• https://github.com/mothenjoyer69/bc250-documentation
• https://github.com/AMD-BC-250/documentation

---

Additional Resources

• BIOS Flashing Guide
• Linux Distribution Setup
• Overclocking Guide
• Cooling Solutions