You mean the one that also has Samsung 7nm euv slim PS4 in fall 2019?
This one:
- 24 GB RAM in total (20 GB usable by games)
- 8 GB in form of 2 * 4-Hi stacks HBM2 - Sony got "amazing" deal for HBM - in part due to them buying up bad chips from other customers which can't run higher then 1.6 Gbps while keeping 1.2v.
- HBM is expected to scale down in price a lot more than GDDR6 over the console lifetime
-Samsung, Micron and SK Hynix already shifting part of their capacity towards HBM due to falling NAND prices -
Sony will be one of the first high volume customers of TSMCs InFO_MS when mass production starts later this year (normal InFo already used by Apple in their iPhone)
- InFO_MS brings down the cost compared to traditional silicon interposers - has thermal and performance advantage as well - InFO_MS allows them to drive their 1.6 Gbps chips @ 1.7 Gbps (435 GB/sec.) without having to increase the voltage above 1.2v
- HBM is more power efficient compared to GDDR6 - the savings were invested into more GPU power - additional 16 GB in form of DDR4 @ 256 bit for 102.4 GB/sec
. - 4 GB reserved for OS, the remaining 12 GB usable by games
- memory automatically managed by HBCC and appears as 20 GB to the developers
- HBCC manages streaming of game data from storage as well - developers can use the API to take control if they choose and manage the memory and storage streaming themselves
- memory solution alleviates problems found in PS4 - namely that CPU bandwidth reduces GPU bandwidth disproportionately
- 2 stacks of HBM have 512 banks (more banks = fewer conflicts and higher utilization)
- GDDR6 better than GDDR5 and GDDR5x in that regard but still less banks than HBM - at the same time trying to keep CPU memory access to slower DDR4
- very satisfied with decision to use two kinds of memory for price to performance reasons