I come here to debunk an false leak (bring here by me) about m2 max UltraFusion, and confirm another.
UltraFusion in m2 Max is at one side just like the m1 max, confirmed thru x-ray on M2 Mac book Pro system board.
That's x-ray also confirm double Data path and what seems a central bifurcation, or if it where separation for two sockets.
It reminded an theory or leak from a Chinese source which states m2 extreme are daisy chained in asymetrical arrangements, which seems me weird but consistent.
From that pair of UltraFusion (name it primary and secondary) one is directed to a root soc and the secondary is connected to the primary UF from child SOC.
How to arrange It along interposers is where speculation comes.
Someone suggested apple could put a pair of m2 Ultra side by side in front another pair in an ladder pattern. This is good for short path bias but also eclipses half ram channels, so an m2 extreme to have the same number of RAM channels as an m2 ultra (8).
An alternative arrangements implies two longer interposer, bit longer as the m2 max, in asymetrical or ladder arrangement the one at left connecting to the precedent or father SOC and the one at right connecting to the child SOC, in implies all m2 max disposed the same alignment (all up, not one up-one down as M1 ultra). Also implies a bit longer Data path but noise in silicon substrates it's easy to handle so it won't affect performance neither stability. But M2 extreme interposer to cost twice each at least and at least 3 are required to interface 4 m2 max.
A diagram:
Both arrangements have its own pro and cons:
S: half ram channels blocked, all thunderbolt and native m2max I/O available. More complicated cooling.
Stacked: only master m2ax I/O available, all memory channels available, easier cooling.
S arrangement also allow for an PCIe5 I/O terminator at each extreme unused UltraFusion, while the stacked arrangement only one (at master/root), given each UF provides 2.5 TB a single PCIe5 UltraFusion terminator is enough for 5 PCIe5 slots, so I bet apple to deploy m2 extreme as a stacked m2 max, teaming 2,3 UpTo 4 soc. As only the master requires all it's I/O provisions.
UltraFusion in m2 Max is at one side just like the m1 max, confirmed thru x-ray on M2 Mac book Pro system board.
That's x-ray also confirm double Data path and what seems a central bifurcation, or if it where separation for two sockets.
It reminded an theory or leak from a Chinese source which states m2 extreme are daisy chained in asymetrical arrangements, which seems me weird but consistent.
From that pair of UltraFusion (name it primary and secondary) one is directed to a root soc and the secondary is connected to the primary UF from child SOC.
How to arrange It along interposers is where speculation comes.
Someone suggested apple could put a pair of m2 Ultra side by side in front another pair in an ladder pattern. This is good for short path bias but also eclipses half ram channels, so an m2 extreme to have the same number of RAM channels as an m2 ultra (8).
An alternative arrangements implies two longer interposer, bit longer as the m2 max, in asymetrical or ladder arrangement the one at left connecting to the precedent or father SOC and the one at right connecting to the child SOC, in implies all m2 max disposed the same alignment (all up, not one up-one down as M1 ultra). Also implies a bit longer Data path but noise in silicon substrates it's easy to handle so it won't affect performance neither stability. But M2 extreme interposer to cost twice each at least and at least 3 are required to interface 4 m2 max.
A diagram:
Code:
Proposed S arrangement:
(Ram)|M2|M2#(Ram)
Π U
(Ram)#W2|W2|(Ram)
Stacked:
(Ram)|M2#(Ram)
↑==↓ (UF below the SOC)
(Ram)|M2|(Ram)
↑==↓
(Ram)|M2|(Ram)
↑==↓
(Ram) M2|(Ram)
# denotes PCIe5 UltraFusion I/O terminator.Both arrangements have its own pro and cons:
S: half ram channels blocked, all thunderbolt and native m2max I/O available. More complicated cooling.
Stacked: only master m2ax I/O available, all memory channels available, easier cooling.
S arrangement also allow for an PCIe5 I/O terminator at each extreme unused UltraFusion, while the stacked arrangement only one (at master/root), given each UF provides 2.5 TB a single PCIe5 UltraFusion terminator is enough for 5 PCIe5 slots, so I bet apple to deploy m2 extreme as a stacked m2 max, teaming 2,3 UpTo 4 soc. As only the master requires all it's I/O provisions.
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