# BIOS VRAM Configuration — HP ZBook Ultra G1a

## Why Change VRAM?

AMD Strix Halo uses **unified memory** — the CPU and GPU share the same physical RAM. By default, the HP ZBook allocates **32 GB as dedicated VRAM**, permanently locking that memory away from the OS even when the GPU isn't using it.

AMD recommends keeping dedicated VRAM at **512 MB** (minimum) and using **GTT (Graphics Translation Table)** for dynamic GPU memory access. With kernel boot parameters, the GPU can access up to ~60 GB on demand while the CPU retains full flexibility.

## Current vs Optimal (64 GB system)

| Setting | Default | Optimal |
|---------|---------|---------|
| Dedicated VRAM | 32 GB | 0.5 GB |
| GTT (dynamic) | ~15.5 GB | ~59 GB |
| OS visible RAM | ~31 GB | ~63.5 GB |

## Steps

1. **Reboot** the laptop
2. Press **F10** repeatedly during boot to enter BIOS Setup
3. Navigate to: **Advanced** > **Built-in Device Options** (or **Display** section)
4. Find: **UMA Frame Buffer Size** (may also be labeled "iGPU Memory" or "VRAM Size")
5. Set to: **512 MB** (or the smallest available option)
6. **Save and Exit** (F10)

> The exact menu path may vary by BIOS version. If you can't find it under "Built-in Device Options", check under "Advanced > Display" or "Chipset Configuration".

## After BIOS Change

1. Ensure kernel boot parameters are configured (run `make optimize-kernel`)
2. Reboot
3. Verify with `make audit`:
   - VRAM should show ~0.5 GiB
   - GTT should show ~59 GiB
   - System RAM should show ~63.5 GiB

## References

- [AMD ROCm Strix Halo Guide](https://rocm.docs.amd.com/en/latest/how-to/system-optimization/strixhalo.html)
- [Strix Halo Toolboxes](https://strix-halo-toolboxes.com/)