Socket TR4, also known as Socket SP3r2, is a zero insertion force land grid array (LGA) CPU socket designed by AMD supporting its first- and second-generation Zen-based Ryzen Threadripper desktop processors,[1][2] launched on August 10, 2017[3] for the high-end desktop and workstation platforms.

It was succeeded by Socket sTRX4 for the third generation of Ryzen Threadripper processors.

[3][6] While the SP3 server socket does not require a chipset, instead utilizing a system-on-a-chip design, TR4 and its successor HEDT sockets require a chipset to unlock the features of the CPU.

For TR4, the AMD X399 chipset was released, which allows a total of 64 PCIe 3.0 lanes for quad SLI/CrossFire configurations.

[7] The socket is made by both Foxconn and Lotes.