How can 4GB memory be supported?

[Laura]

that was a hot topic before the release of z8x00 based products.

technically, they do it by just using more dense (so, higher capacity per chip) ram modules on the single channel that is available on z8300, instead of using both channels that are available only on z8500 and z8700.

as to why intel says z8300 is limited to 2gb, they probably intended it to be that way but forgot to put a restriction in place and just decided it’s better of this way (if intel wanted, they could have locked z8300s rather easily either via bios or microcode so they must have decided to let it slip)

[Jonathan]

For what it’s worth I looked into this issue and came to the conclusion that all of the z8000 series SoC use the same memory controller but that since the z8300 only exposes one channel (all the pins required, I checked) to the outside world it can only support half the memory. The 2GB limit, I concluded, applied only to DDR3L-RS devices and that with LPDDR3 devices you could get 4GB (the SoC supports DDR3L-RS devices with only a 16-bit data width but LPDDR3 devices with 32-bit data width).

For more information look at volume one of the datasheet, tables 58 and 59(page 106)  and table 60(page 107), don’t make the mistake of confusing gigabit (Gb) and gigabyte(GB) .

Essentially this supports what @Laura said.

However, I don’t think this was an error on Intel’s part and, although I might be missing something obvious, I can’t see how Intel could have easily limited the memory supported using microcode or BIOS (the former I think is limited to the CPU cores and the later normally being in the realm of another company).

[Author]

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