BIOS Setup¶

MS-S1 MAX specific BIOS configuration for optimal performance with AMD APU workloads.

Authoritative spec sheet: minisforum.com/products/ms-s1-max.

Firmware Version¶

Run BIOS 1.06 (released 2026-01-04) or later before installing Ubuntu 26.04. Earlier firmware has known memory training, NVMe, and USB4 v2 stability issues that 26.04's Linux 7.0 kernel exposes more aggressively.

The flash is doable from Linux + EFI shell — see capetron/minisforum-ms-s1-max-bios. Disable Secure Boot during the flash and expect 5-10 minutes of memory retraining on the first boot afterwards (BIOS settings reset to defaults).

Rear USB4 ports

A known ACPI power-management flaw on the rear USB4 v2 (80 Gbps) ports is not fully resolved by 1.06 as of early 2026. Prefer the front 40 Gbps USB4 ports for any device where stability matters.

Accessing BIOS¶

Power on the system and press the appropriate key during POST:

Method	Key
Primary	Del
Alternative	F2

Timing

Press the key repeatedly as soon as you see the Minisforum logo. USB keyboards may have a slight delay.

Memory Settings¶

Memory configuration is critical for APU performance since the integrated GPU shares system RAM.

Soldered LPDDR5X — no XMP/DOCP

The MS-S1 MAX ships with 128GB LPDDR5X-8000 MT/s on a 256-bit (quad-channel) bus, soldered to the SoC package. There are no DIMM slots, no XMP/DOCP profile to enable, and memory speed is fixed by firmware. The only memory-related knobs in BIOS that matter on this platform are the UMA frame buffer size (below) and the AMD CBS memory interleaving toggles.

UMA Frame Buffer Size¶

The UMA (Unified Memory Architecture) Frame Buffer allocates a portion of system RAM as dedicated video memory for the integrated GPU:

Setting	Location	Recommended
UMA Frame Buffer	Advanced > Graphics	512 MB (small)
VRAM Size	(same setting, different name)	512 MB (small)

Setting options explained:

Value	Use Case
512MB	Recommended for Strix Halo + AI workloads — keep dedicated VRAM small, use GTT for the rest
1-4GB	Desktop/server with mixed light GPU workloads
8-16GB	Only if a workload specifically requires large fixed VRAM and cannot use GTT
32GB+	Rarely useful — locks RAM away from the OS

AMD's official Strix Halo guidance

AMD's ROCm system-optimization guide recommends keeping dedicated VRAM small (~0.5 GB) and letting GTT-backed allocations dynamically use up to ~50% of system RAM (raisable via amd-ttm). Large UMA reservations were the right answer on older APUs but on Strix Halo they just take RAM out of the OS pool without giving ROCm anything it couldn't get via GTT. See Memory Configuration for the runtime knobs.

Memory Interleaving¶

Ensure channel and bank interleaving are enabled so the SoC actually uses the 256-bit bus:

Setting	Location	Recommended
Channel Interleaving	Advanced > Memory	Auto or Enabled
Bank Interleaving	Advanced > Memory	Auto or Enabled

Verify memory presentation from Linux. Because the LPDDR5X is on-package, dmidecode will report it as soldered/embedded (sometimes with non-standard slot strings, depending on firmware):

sudo dmidecode -t memory | grep -E "Speed|Locator|Size|Form Factor"

You should see ~8000 MT/s reported and a single 128GB total. There are no socketed DIMM slots to populate.

AMD APU Settings¶

IOMMU (AMD-Vi)¶

Required for virtualization and GPU passthrough:

Setting	Location	Recommended
IOMMU	Advanced > AMD CBS	Enabled
ACS Enable	Advanced > AMD CBS	Enabled (if available)

Verify from Linux:

dmesg | grep -i iommu

Above 4G Decoding¶

Allows PCIe devices to use memory addresses above 4GB:

Setting	Location	Recommended
Above 4G Decoding	Advanced > PCI	Enabled
Re-Size BAR	Advanced > PCI	Enabled

Re-Size BAR (Resizable BAR) enables the CPU to access the full GPU memory range, beneficial for some workloads.

iGPU Configuration¶

Setting	Location	Recommended
Primary Display	Advanced > Graphics	Auto or IGFX
iGPU Multi-Monitor	Advanced > Graphics	Enabled (if using displays)

For headless server operation, these settings have minimal impact. The iGPU remains available for compute regardless.

CPU Settings¶

Precision Boost Overdrive (PBO)¶

PBO allows the CPU to boost beyond stock limits when thermal and power headroom exists:

Setting	Location	Recommended
PBO	Advanced > AMD CBS > SMU	Advanced or Enabled
PBO Limits	Advanced > AMD CBS > SMU	Auto

For 24/7 server operation, consider:

Conservative: PBO Disabled - Stable, predictable power
Balanced: PBO Auto - Reasonable boost, default behavior
Performance: PBO Advanced - Maximum performance, higher power/heat

SMT (Simultaneous Multi-Threading)¶

Setting	Location	Recommended
SMT	Advanced > AMD CBS	Enabled

SMT provides 32 threads from 16 cores. Disable only if specific workloads perform better with SMT off (rare for server workloads).

cTDP / TDP Settings¶

If available, configure power limits:

Setting	Description
cTDP	Configurable TDP limit
PPT	Package Power Tracking limit
TDC	Thermal Design Current limit
EDC	Electrical Design Current limit

For 24/7 operation, stock settings provide a good balance. Increase only if cooling is adequate.

Power and Thermal Settings¶

Power Profile¶

Setting	Location	Recommended
Power Profile	Advanced > Power	Balanced or Performance
Package Power Limit	Advanced > Power	Auto

For server use:

Balanced - Good performance, reasonable power
Performance - Maximum speed, higher power draw
Low Power - Reduced performance, quieter operation

AC Power Recovery¶

Important for unattended operation:

Setting	Location	Recommended
AC Power Loss	Advanced > Power	Power On
Power On After Power Fail	(same)	Always On

This ensures the server restarts automatically after power outages.

Fan Control¶

Setting	Location	Recommended
Fan Mode	Hardware Monitor or Advanced > Thermal	Auto or Silent
Fan Curve	(if available)	Custom

For 24/7 operation, prioritize cooling over noise. The system should maintain safe temperatures under sustained load.

Virtualization Settings¶

For KVM/QEMU virtual machines:

Setting	Location	Recommended
SVM	Advanced > CPU	Enabled
IOMMU	Advanced > AMD CBS	Enabled
NX Mode	Advanced > CPU	Enabled
SME	Advanced > AMD CBS	Enabled (optional)

SVM (Secure Virtual Machine) is AMD's virtualization technology, equivalent to Intel VT-x.

Boot Settings¶

Setting	Location	Recommended
Boot Mode	Boot	UEFI
Secure Boot	Boot > Security	Disabled (recommended for this build — see note below)
Fast Boot	Boot	Disabled
Boot Order	Boot	NVMe first

Secure Boot is disabled for this build

This setup uses out-of-tree DKMS modules (amdgpu-dkms, zfs-dkms) which must be MOK-signed to load under Secure Boot. The simpler, lower-friction path is to keep Secure Boot disabled on this headless server. The host is protected by network controls (UFW, Tailscale-only management), not boot-time integrity. If you specifically need Secure Boot, plan to enroll a MOK before installing ROCm or ZFS.

Settings Summary¶

Quick reference for AI/server workloads:

Category	Setting	Value
Memory	UMA Frame Buffer	512 MB (Strix Halo: keep small, use GTT)
AMD	IOMMU	Enabled
AMD	Above 4G Decoding	Enabled
AMD	Re-Size BAR	Enabled
CPU	PBO	Auto or Enabled
CPU	SMT	Enabled
Power	AC Power Loss	Power On
Boot	Boot Mode	UEFI
Boot	Secure Boot	Disabled (simpler for amdgpu/ROCm/ZFS DKMS)

Saving and Exit¶

After making changes:

Press F10 or navigate to Exit > Save Changes and Reset
Confirm saving changes
System will reboot with new settings

Verifying Settings from Linux¶

After booting Ubuntu, verify BIOS settings took effect:

# Check memory speed
sudo dmidecode -t memory | grep Speed

# Check IOMMU
dmesg | grep -i -e DMAR -e IOMMU

# Check Resizable BAR
lspci -vvv | grep -i "resize"

# Check virtualization
grep -E 'svm|vmx' /proc/cpuinfo

# Check PBO/boost status
cat /sys/devices/system/cpu/cpu0/cpufreq/boost