Intel Xeon Phi 7285 socket: LGA 3647

What the Xeon Phi 7285 is

The Xeon Phi 7285 is a sixty eight core, two hundred seventy two thread many core accelerator from Knights Mill. It launched in December 2017 with a 1.3 GHz base and up to 1.4 GHz Turbo at 250 W. Sixty eight cores cover HPC training nodes where throughput matters most.

Thirty four megabytes of shared L2 cache feed sixty eight cores. The 1.3 GHz base sustains all core throughput, while 1.4 GHz burst helps setup tasks. Two hundred fifty watts suit single socket HPC nodes.

Sixteen gigabytes of MCDRAM at high bandwidth plus six channel DDR4-2400 up to 384 GB hold models and datasets. MCDRAM cache mode speeds hot loops without code changes. Flat mode gives explicit control where tuned.

Knights Mill doubles single precision over Knights Landing with new neural instructions for mixed precision integers. Training throughput rises up to four times on deep learning kernels per Intel Hot Chips guidance. Locked multiplier keeps clusters consistent.

Socket and motherboard compatibility

The 7285 fits LGA 3647 on HPC boards with Phi firmware. BIOS must list 68 core Knights Mill parts. Single socket per node is the design.

Boards configure MCDRAM as cache, flat or hybrid per workload. DDR4-2400 ECC holds large memory footprints. The Socket vs chipset: what decides whether a CPU works guide covers server generations.

The Xeon Phi 7295 on the same socket adds four cores and clocks. The 7235 trims cores where cost matters.

Memory, PCIe and cooling

DDR4-2400 ECC in six channels up to 384 GB plus 16 GB MCDRAM is the design. Bandwidth peaks near 115.2 GB per sec on DDR4 plus 400+ GB/s on MCDRAM. ECC protects long training runs.

Sixteen PCIe lanes wire fabric and NVMe. HPC fabrics take priority slots. Node boot uses DDR4 while compute stays in MCDRAM where tuned.

Two hundred fifty watts need high airflow server cooling. Data center set points decide sustained throughput.

Upgrade paths

On LGA 3647 the step is Phi 7295 for more cores and higher clocks, reusing board and memory where firmware allows it.

Past Phi Intel moved training to other accelerators, so growth means new platforms. Fabric and storage upgrades often help clusters more.