I have seen video. There stated exactly: CPU don't have access to GPU cache, because "they have ran tests, and with this configuration some applications seen tw

I have seen video. There stated exactly: CPU don't have access to GPU cache, because "they have ran tests, and with this configuration some applications seen two digits speed increase, but nearly none applications they tested shown significant gains with CPU have access to GPU cache". So, when CPU access GPU memory, CPU just directly access RAM via system bus, but not trying to check GPU cache. And yes, this mean, could be large delay between GPU write cache and data actually delivered to RAM and seen by CPU, but probably, smaller than on discrete GPU on PCIe.