Intel Xeon 6978P socket: LGA 7529

What the Xeon 6978P is

The Xeon 6978P is a 120-core, 240-thread server processor that Intel released in July 2025 near the top of the Xeon 6900P series. It uses Granite Rapids P-cores on the Intel 3 process. Base clock is 2.1 GHz with maximum turbo up to 3.9 GHz and all-core turbo at 3.2 GHz. Shared L3 cache totals 504 MB, the largest in this batch, and Intel rates the processor base power at 500 W.

Against the 72-core Intel Xeon 6944P the 6978P adds 48 cores and 72 MB of cache for hosts that sell virtual machines or run large in-memory databases. Against the 72-core Intel Xeon 6962P at the same 500 W it trades clock speed for core count: the 6962P boosts higher per core, while the 6978P finishes threaded work faster. Power delivery and cooling must be sized for the full 500 W class either way.

As with the rest of the series there is no integrated graphics and the multiplier is locked. ECC memory is supported, including the faster MRDIMM option at up to 8800 MT/s. Two threads per core give 240 threads per socket, or 480 across a filled pair. That density suits hosts that consolidate many virtual machines onto few sockets to save licenses tied to socket count.

Socket and motherboard compatibility

The 6978P fits the LGA 7529 socket on the Birch Stream platform in the FCLGA7529 package with a BR1A carrier. Only purpose-built server boards accept it. The socket shares nothing with desktop LGA sockets, and the smaller LGA 4710 server platform takes different Granite Rapids SKUs with fewer memory channels.

Systems scale to two sockets over six UPI links. Board choice matters more than usual at 500 W because voltage regulation, airflow shrouds and heatsink retention all assume specific thermal envelopes. Confirm the 6978P by name on the board maker CPU support list and the minimum BIOS before purchase.

Buyers comparing core types can look at the Intel Xeon 6980E+ on the same socket, a Clearwater Forest E-core part with 264 threads for density-first hosting. P-cores keep the advantage where per-core licensing or single-thread pace dominates the bill.

Memory, PCIe and cooling

Memory support covers DDR5 up to 6400 MT/s and MRDIMM up to 8800 MT/s across 12 channels per socket, with up to 3 TB of capacity. The MRDIMM option raises bandwidth for memory-bound analytics and virtualization where many cores feed from the same pool. Populate all 12 channels per socket to keep the 120 cores fed; half-populated boards leave performance on the table.

Expansion provides up to 96 PCIe 5.0 lanes from the CPU with CXL 2.0 support for memory expansion and accelerators. High-speed networking, NVMe fleets and GPU or FPGA cards attach here, with exact slot widths set by the board design. The platform hub handles remaining board I/O outside these CPU lanes.

At 500 W only vendor-qualified heatsinks apply, spanning high-performance air for 2U and taller chassis plus direct liquid cooling for dense racks. No cooler ships with the processor. The board vendor thermal guide sets the approved list per chassis, and installers should follow its torque andTIM guidance rather than desktop habits. See the CPU cooler compatibility by socket guide for background on mounting patterns.

Upgrade paths

Inside LGA 7529 the 6978P is close to the ceiling for P-core count, so upgrades from smaller Granite Rapids SKUs such as the Intel Xeon 6944P land here when virtual machine density becomes the limit. The swap keeps boards, memory and PCIe cards while raising power to 500 W, so cooling and power budgets need rechecking. Cache grows from 432 MB to 504 MB in the same step.

Lateral moves include the Intel Xeon 6962P for higher clocks at fewer cores, or Clearwater Forest E-core parts such as the Intel Xeon 6980E+ for thread density per watt. Leaving the platform means new boards on LGA 4710 or later sockets, with fresh memory and heatsink qualification.