How much would an I/O die in 7nm be different between DDR4 and DDR5.
If not much difference I think Zen3 may already have an 7nm I/O die, the APU has the 7nm I/O
I don't think it's a big issue to have the same die for DDR4 and DDR5 (obviously it can only do one when it is assembled/configured)
Advantage:
You don't have to make the I/O die again for DDR5 if you already keep DDR5 in mind.
Earlier/easier testing for AM5 platform. (all circuits not for DDR5 on the I/O die have already been tested)
Easily switch demand for DDR4 or DDR5 with the same die.
A bit less heat for Zen3 CPU
Both dies are produced by the same manufacturer. (cheaper/easier logistics)
Disadvantage:
Will take a little more die space with DDR5 support.
The die has to be ready earlier, for Zen3 launch. So it's a time gamble because if it's too late everything of Zen3 shifts in time.
So did they play safe just using the old die or take the risk....
If not much difference I think Zen3 may already have an 7nm I/O die, the APU has the 7nm I/O
I don't think it's a big issue to have the same die for DDR4 and DDR5 (obviously it can only do one when it is assembled/configured)
Advantage:
You don't have to make the I/O die again for DDR5 if you already keep DDR5 in mind.
Earlier/easier testing for AM5 platform. (all circuits not for DDR5 on the I/O die have already been tested)
Easily switch demand for DDR4 or DDR5 with the same die.
A bit less heat for Zen3 CPU
Both dies are produced by the same manufacturer. (cheaper/easier logistics)
Disadvantage:
Will take a little more die space with DDR5 support.
The die has to be ready earlier, for Zen3 launch. So it's a time gamble because if it's too late everything of Zen3 shifts in time.
So did they play safe just using the old die or take the risk....