Intel Xeon Gold 6438Y+ socket: LGA 4677

What the Xeon Gold 6438Y+ is

In the Sapphire Rapids Gold stack, the Xeon Gold 6438Y+ serves as the 32-core member of the 4th Gen Xeon Scalable family for LGA 4677 boards from January 2023. 32 cores with hyperthreading give 32 cores and 64 threads, with base at 2.0 GHz and up to 4.0 GHz turbo. The package carries 60 MB of Smart Cache. The 205 W envelope fits standard server heatsinks with front to back airflow.

DDR5 to 4800 MT/s with one DIMM per channel and 4400 MT/s with two DIMMs per channel in 8 channels with ECC feeds the cores, and matched DIMMs hold the rated speed. Eighty Gen5 lanes with Flex Bus and CXL per CPU wire NICs, accelerators and NVMe, and the lane count stays constant across most Sapphire Rapids Gold and Platinum SKUs. Three UPI links at 16 GT/s join two sockets into a coherent pair, while larger four socket and eight socket fabrics use the H class SKUs instead.

Dense virtualization, hyperconverged nodes and AI data preparation take this core count with 60 MB of shared cache, where thread density per socket reduces node count. Server boards need a C741 class chipset with the Xeon Gold 6438Y+ 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 5411N shows a nearby Xeon Gold option on the same socket.

Socket and motherboard compatibility

The 6438Y+ fits LGA 4677 on single and dual socket server boards with LGA 4677 retention and server power delivery. Board lists must name the Xeon Gold 6438Y+ suffix 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 Sapphire Rapids Gold and Platinum from January 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 in dual socket pairs.

Memory, PCIe and cooling

DDR5 to 4800 MT/s with one DIMM per channel and 4400 MT/s with two DIMMs per channel in 8 channels with ECC feeds the cores, and matched DIMMs hold the rated speed. Population with matched RDIMMs 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, which suits in memory work on 32 cores.

Eighty Gen5 lanes with Flex Bus and CXL per CPU wire NICs, accelerators and NVMe, and the lane count stays constant across most Sapphire Rapids Gold and Platinum SKUs. CXL memory expansion and accelerators share 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 205 W envelope fits standard server heatsinks with front to back airflow. 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 205 W parts.

Upgrade paths

On LGA 4677 the upward moves are higher core Xeon Gold parts where VM counts grow, or adding a second Xeon Gold 6438Y+ socket where boards allow two socket operation. For this 32-core SKU, memory growth to full eight channel population and NIC additions often help more than clocks. Moving from DDR5 to 4800 MT/s in 8 channels to fully populated channels lifts bandwidth without a CPU swap.

Outside this SKU, Intel Xeon Gold 5411N (Xeon Gold 5411N) on LGA 4677 trims or adds cores for lighter or denser loads. Platinum parts add UPI breadth for four socket and eight socket 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.