Dual-mode, one QoS plane
JESD270-4 (2048-bit interposer) and JESD330-4 (512-bit organic, 4:1) present the same 32 logical channels and the same credit plane to Stallion. First tape-out is H4-only; the S4 wrapper is a stub.
Technology
Bandwidth is an identity, not a marketing sample. The formulas on this page are the same ones the product lock is required to print.
B_stack = (W_DQ × R_pin) / 8000 TB/s
B_agg = B_stack × N_stacks
t_CK = 2 / R_pin ns (DDR; 8 Gbps ⇒ 0.250 ns)
C_GB = N_hi × D_die,Gb / 8
P_FP32 = N_SM × N_ALU × 2 × f_GHz / 1000000 PFLOPS
2048-bit × 8 Gbps / 8 = 2.048 TB/s per stack. Eight stacks = 16.0 TB/s sustained across an aggregate 16,384-bit wide bus. 16-Hi × 32 Gb / 8 = 64 GB per stack. Eight cubes = 512 GB unified HBM4 memory pool on 3Dx3D Glass Core Substrate.
Same DRAM stacks, 512-bit external interface, 4:1 serialization. 512 × 32 / 8000 = 2.048 TB/s if and only if the external rate is the 4×8 identity. That is arithmetic, not a datasheet bin.
FairView policy
These are proprietary product architectures and trade secret claim directions. JEDEC maps, DRFM, and UCIe itself are not ours.
JESD270-4 (2048-bit interposer) and JESD330-4 (512-bit organic, 4:1) present the same 32 logical channels and the same credit plane to Stallion. First tape-out is H4-only; the S4 wrapper is a stub.
Stallion issues idle-window credits from wavefront drain, barriers, and L2 miss-queue occupancy. Gallium prefers those windows for refresh and directed refresh. Periodic refresh still fires if credits do not arrive.
A firmware remap table isolates MIG tenants or a second Stallion die. The stack always sees legal CH0–CH31. Remap is drain-then-commit — never mid-burst.
Command, credit, thermal class, and RAS events ride a closed opcode set. There is no data-beat type. HBM read/write never rides UCIe.
Cube, controller, and SM sensors fuse into four discrete classes. Class raises refresh weight, demotes unhinted QoS, and at class 3 requests a Stallion clock re-lock. No invented junction-temperature datasheet.
| Opcode | Direction | Payload |
|---|---|---|
| CREDIT_UPD | Gallium → Stallion | Per-PC / per-class credits |
| HINT_WINDOW | Stallion → Gallium | Idle-cycle grant, urgency |
| THERM_BIN | Both | Discrete thermal class 0–3 |
| RAS_EVENT | Gallium → Stallion | Poison, replay, channel down |
| MAP_COMMIT | Stallion → Gallium | Remap table CRC |
| LINK_HB | Both | Heartbeat |