- [Reddit thread of what is needed for GPU passthrough](https://www.reddit.com/r/Qubes/comments/9hp3e7/gpu_passthrough_howto/)
- [Solution to have more than 3Go of RAM in the Windows HVM](https://github.com/QubesOS/qubes-issues/issues/4321#issuecomment-423011787)
- [Some old references](https://www.reddit.com/r/Qubes/comments/66wk4q/gpu_passthrough/)
## Prerequise
You have a functional Windows 7 HVM.
The "how to" for this part can be found on the Qubes OS documentation and here: [Usefull github comment](https://github.com/QubesOS/qubes-issues/issues/3585#issuecomment-453200971).
However, few tips:
- Do a backup (clone VM) of the Windows HVM BEFORE starting to install QWT
- The Windows user MUST BE "user"
- Windows 7 Only, do not use Windows 10 or others.
## Hardware
To have a Windows HVM for gaming, you must have:
- A dedicated AMD GPU. By dedicated, it means: it is a secondary GPU, not the GPU used to display dom0. Nvidia GPU are not supported (or maybe with a lot of trick).
- In dom0, you edited the file `/etc/default/grub` or `/boot/efi/EFI/qubes/xen.cfg` to allow PCI hiding for your secondary GPU, and regenerated the grub if needed
Follow the instructions here: [https://github.com/QubesOS/qubes-issues/issues/4321#issuecomment-423011787](https://github.com/QubesOS/qubes-issues/issues/4321#issuecomment-423011787)
Copy-paste of the comment:
```
This is caused by the default TOLUD (Top of Low Usable DRAM) of 3.75G provided by qemu not being large enough to accommodate the larger BARs that a graphics card typically has.
The code to pass a custom max-ram-below-4g value to the qemu commandline does exist in the libxl_dm.c file of xen, but there is no functionality in libvirt to addthis parameter.
It is possible to manually add this parameter to the qemu commandline by doing the following in a dom0 terminal: