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Comment by luyu_wu

1 day ago

The iGP can access shared memory the same as with any modern system. I'm confused where you got this idea from.

There is a huge difference between on-die and off-die memory. Where that shared memory is located matters immensely.

  • Assuming you're referring to Apple Silicon's memory bandwidth, that is not necessarily because the memory is on-die. The bandwidth comes from having more channels to access memory. This gives the SoC a wider bus to increase throughput vs. your typical x86 system with two channels. For whatever reasons Intel/AMD decided that two channels is all the typical consumer chips can support now so it's on them.

  • You mentioned Strix Halo, which also has off-die memory. Strix Halo does have a real advantage from its wider memory bus (four channels for 256 bit instead of 128 bit), but Strix Point is equivalent-ish to Intel's platforms like Panther Lake or Arrow Lake in terms of memory setup.

    In fact, Intel also had Lunar Lake, which had on-package memory. However, it was still limited to 128-bit dual-channel, so there weren't really many performance benefits; it did however help with power efficiency.

  • I appreciate everyone's corrections here, my apologies. I clearly misunderstood the situation.

  • Macs or other competing systems don't have on-die memory.

    (Except for the caches, which everybody has)

  • Nonsense, Apple has on package memory and the primary reason for that is overall packaging and layout not performance