Intel Xeon Platinum 8558 socket: LGA 4677

What the Xeon Platinum 8558 is

The Intel Xeon Platinum 8558 is the 48-core member of the 5th Gen Xeon Scalable family for LGA 4677 boards from December 2023. 48 cores with hyperthreading give 48 cores and 96 threads, with base at 2.1 GHz and up to 4.0 GHz turbo. The package carries 260 MB of Smart Cache. The 330 W envelope needs a high capacity server heatsink with front to back airflow and a chassis rated for continuous full load.

Up to DDR5 5200 MT/s, 8 channels, up to 4 TB with ECC feed the cores, and matched DIMMs hold the rated speed. Eighty Gen5 lanes per CPU wire NICs, accelerators and NVMe. Four UPI links at 20 GT/s join sockets into a coherent fabric on Emerald Rapids, while board firmware sets the exact topology.

Large scale virtualization and in memory analytics take this 48-core Platinum with more than 250 MB of shared cache, where socket count and fabric matter as much as clocks. Boards need a C741 class chipset with the Xeon Platinum 8558 on the CPU support list, not W790 workstation boards. The Socket vs chipset: what decides whether a CPU works guide covers server board choice, and Intel Xeon Gold 6554S shows a nearby option on the same socket.

Socket and motherboard compatibility

The 8558 fits LGA 4677 on single and dual socket server boards with LGA 4677 retention and server power delivery. Board lists must name the Xeon Platinum 8558 part for qualification. W790 workstation boards target W-series chips instead, so a server SKU will not post there even though the contact count matches.

Server chipset choice decides management and IO breadth rather than CPU fit. C741 class boards carry BMC management, multiple NICs and NVMe backplanes for this power class. A BIOS that lists Emerald Rapids from December 2023 covers the part, while early firmware may need an update for specific stepping IDs. Check the board CPU list before mixing this SKU with other steppings.

Memory, PCIe and cooling

Up to DDR5 5200 MT/s, 8 channels, up to 4 TB with ECC feed the cores, and matched DIMMs hold the rated speed. Population with matched DIMMs holds the rated speed, and eight channel operation needs one DIMM per channel at minimum for full bandwidth. Capacity reaches 4 TB per socket with high density DIMMs.

Eighty Gen5 lanes per CPU wire NICs, accelerators and NVMe. CXL memory expansion shares the same fabric on boards that wire those slots to CPU lanes. Lane bifurcation follows board firmware, so slot population rules come from the board manual.

The 330 W envelope needs a high capacity server heatsink with front to back airflow and a chassis rated for continuous full load. The 77.5 × 56.5 mm FCLGA4677 package uses a server carrier with even mounting pressure. Paste and torque sequence follow the heatsink maker specification for 330 W parts.

Upgrade paths

On LGA 4677 the upward moves are higher core Platinum parts where VM counts grow, or adding a second Xeon Platinum 8558 socket where boards allow two socket operation. For this 48-core SKU, memory growth to full eight channel population and NIC additions often help more than clocks.

Outside this SKU, Intel Xeon Gold 6554S (Xeon Gold 6554S) on LGA 4677 trims or adds cores for lighter or denser loads. Platinum parts add UPI breadth for larger fabrics, while Silver parts cut cost for single purpose hosts. A move to another socket needs a new board and memory plan, so socket local growth comes first.