Resizing bar for AMD APUs

[Sparseic]

Will resizing the bar of my APU from 512MB to lets say 4GB safe? I have an AMD Ryzen 5 4600G and a Gigabyte B450M DS3H V2 with 16GB of RAM (The max vram my APU can have is 2GB).

 

Haven't tried it yet but I've seen the options in my BIOS, just haven't saved them and such.

 

I'm still saving up for a new GPU so for the mean time I'm trying to find ways to boost my performance.

[Eigenvektor]

Resizable Bar allows the CPU to address all of a GPUs memory as a single contiguous block. That only really makes sense for a discrete GPU, where the GPU has its own memory (VRAM). An iGPU already shares a CPUs memory.

 

That is not the same as increasing the amount of RAM reserved for your iGPU. That will simply give it more memory, while decreasing the memory available to the CPU. It is safe, it simply means you might run out of RAM sooner, in cases where you're almost using all available memory right now.

[Sparseic]

8 hours ago, Eigenvektor said:

Resizable Bar allows the CPU to address all of a GPUs memory as a single contiguous block. That only really makes sense for a discrete GPU, where the GPU has its own memory (VRAM). An iGPU already shares a CPUs memory.

 

That is not the same as increasing the amount of RAM reserved for your iGPU. That will simply give it more memory, while decreasing the memory available to the CPU. It is safe, it simply means you might run out of RAM sooner, in cases where you're almost using all available memory right now.

Will it impact anything power-wise or will it just be the same as when you're generally using your PC without doing the option?

Actually are there any other way to maybe allocate more / bypass the max VRAM my CPU can have or is 2GB truly the max?

[Eigenvektor]

2 hours ago, Sparseic said:

Will it impact anything power-wise or will it just be the same as when you're generally using your PC without doing the option?

It shouldn't impact anything as far as the desktop is concerned.

 

By default the CPU can access the GPUs memory in 256 MB chunks.

 

So if, for example, it wants to upload 2 GB of data into VRAM that will require 8x256 MB writes.

 

When reBar is enabled, the CPU can access all of the GPUs VRAM at once. So it can do the upload in a single write operation.

 

This can improve performance in some games. More performance means higher fps, which typically also means more power is used.

 

As I said, reBar doesn't change anything about how much memory your iGPU has. If it is limited to 2 GB, enabling reBar doesn't change anything about that.

 

Performance improvements for iGPUs typically means using faster memory (XMP/manual overclock). But since the iGPU itself is rather weak, there's a limit to how much improvement you can get. That's also why you're typically limited to e.g. 2 GB. The iGPU is simply to weak to be able to take advantage of more than that.