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The Switch also has unified memory, which is a tremendous boost to performance for certain types of gaming workloads. The same doesn't apply to PC even if you'r

The Switch also has unified memory, which is a tremendous boost to performance for certain types of gaming workloads. The same doesn't apply to PC even if you're using a desktop iGPU, because the memory model is different.

em500 3y ago
The article shows that Intel and AMD's desktop iGPUs have higher bandwidth and lower latency than the Switch's X1.
- kevingadd 3y ago
  Unified Memory is not about bandwidth or latency. On a desktop PC, you have CPU and GPU side buffers with different addresses that may or may not map to the same physical memory, and the APIs require you to perform mapping/unmapping operations or perform explicit uploads and downloads. On target with unified memory, it is all one address space, the data is just where you put it. There are not split CPU and GPU memory modules. (For some consoles there are different categories of memory, usually based on traits like write combining, but it's all one unified address space). Even now with Vulkan, the experience of programming for a unified memory console is very different. A desktop PC driver can, ideally, optimize out many of your upload/download/map/unmap operations. With unified memory, they simply don't exist.
  - _ph_ 3y ago
    And it hast to be noted that the Apple Silicon has also a unified memory architecture. It should allow for some interesting gaming performance if any developer tries to fully optimize for it.
  - kimixa 3y ago
    Modern GPUs allow mapping memory through PCIe, so you can treat memory as the same. Resize-able BAR effectively allows the same the other way, where all the GPU vram can be mapped into the CPU. The issue is that suddenly accessing an address can have orders of magnitude lower bandwidth and higher latency, if it is resident on the far memory bus. So for performance reasons you still really need to treat them differently.
masklinn 3y ago
IGPs have had unified memory for more than a decade. Consoles use variants of those. Whether toolkits on PCs can transparently make use of unified memory when on IGPs though I could not tell you, and I would not expect game devs to cater much to that.
hedgehog 3y ago
Is there any reason the hardware on say Intel integrated GPU hardware shouldn't be able to do the same? Even outside of gaming the rise of composited desktops seems like motivation to push for low copy + low latency graphics systems.

em500 3y ago

The article shows that Intel and AMD's desktop iGPUs have higher bandwidth and lower latency than the Switch's X1.

kevingadd 3y ago
Unified Memory is not about bandwidth or latency. On a desktop PC, you have CPU and GPU side buffers with different addresses that may or may not map to the same physical memory, and the APIs require you to perform mapping/unmapping operations or perform explicit uploads and downloads. On target with unified memory, it is all one address space, the data is just where you put it. There are not split CPU and GPU memory modules. (For some consoles there are different categories of memory, usually based on traits like write combining, but it's all one unified address space). Even now with Vulkan, the experience of programming for a unified memory console is very different. A desktop PC driver can, ideally, optimize out many of your upload/download/map/unmap operations. With unified memory, they simply don't exist.
- _ph_ 3y ago
  And it hast to be noted that the Apple Silicon has also a unified memory architecture. It should allow for some interesting gaming performance if any developer tries to fully optimize for it.
- kimixa 3y ago
  Modern GPUs allow mapping memory through PCIe, so you can treat memory as the same. Resize-able BAR effectively allows the same the other way, where all the GPU vram can be mapped into the CPU. The issue is that suddenly accessing an address can have orders of magnitude lower bandwidth and higher latency, if it is resident on the far memory bus. So for performance reasons you still really need to treat them differently.

masklinn 3y ago

IGPs have had unified memory for more than a decade. Consoles use variants of those. Whether toolkits on PCs can transparently make use of unified memory when on IGPs though I could not tell you, and I would not expect game devs to cater much to that.

hedgehog 3y ago

Is there any reason the hardware on say Intel integrated GPU hardware shouldn't be able to do the same? Even outside of gaming the rise of composited desktops seems like motivation to push for low copy + low latency graphics systems.