CPU confused specs

[H784]

I have a confusion about Intel i5 12400f desktop CPU .
Official Website says it has max 20 pcie lanes. And pcie configurations are 1x16+4, 2x8+4. So is this 4 lanes for chipset reservation or for SSD? I am confused. Can any expert here help me resolve my confusion?

[n_scott_pearson]

Yes, those 4 PCIe lanes are typically used for a NVMe SSD. This will be the highest performing NVMe SSD interface; the others are supported by PCIe lanes generated by the chipset (PCH component), which all share access to the processor over the DMI bus.
...S

[H784]

If I had a GPU which requires 16 lane and and nvme ssd which requires 4 lane , if GPU and SSD possess 16 + 4 lane , where are the reserved CPU pcle lanes for chipset ? If I ain't wrong, 4 CPU pcie lane is reserved for chipset and
they will share brandwdith between them.