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by lambda 91 days ago
> Only Apple has the unique dynamic allocation though.

What do you mean? On Linux I can dynamically allocate memory between CPU and GPU. Just have to set a few kernel parameters to set the max allowable allocation to the GPU, and set the BIOS to the minimum amount of dedicated graphics memory.
1 comments
AzN1337c0d3r 91 days ago
Maybe things have changed but the last time I looked at this, it was only max 96GB to the GPU. And it isn't dynamic in the sense you still have to tweak the kernel parameters, which require a reboot.

Apple has none of this.

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the_pwner224 91 days ago
Strix Halo you can get at least 120 GB to the GPU (out of 128 GB total), I'm using this configuration.

Setting the kernel params is a one-time initial setup thing. You have 128 GB of RAM, set it to 120 or whatever as the max VRAM. The LLM will use as much as it needs and the rest of the system will use as much it needs. Fully dynamic with real-time allocation of resources. Honestly I literally haven't even thought of it after setting those kernel args a while ago.

So: "options ttm.pages_limit=31457280 ttm.page_pool_size=31457280", reboot, and that's literally all you have to do.

Oh and even that is only needed because the AMD driver defaults it to something like 35-48 GB max VRAM allocation. It is fully dynamic out of the box, you're only configuring the max VRAM quota with those params. I'm not sure why they choice that number for the default.

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lambda 91 days ago
You do have to set the kernel parameters once to set the max GPU allocation, I have it set to 110 GiB, and you have to set a BIOS setting to set the minimum GPU allocation, I have it set to 512 MiB. Once you've set those up, it's dynamic within those constraints, with no more reboots required.

On Windows, I think you're right, it's max 96 GiB to the GPU and it requires a reboot to change it.

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