The pin layout of AMD's Ryzen Threadripper sTRX4 and TR4 sockets has been detailed by Hwbattle who have compiled a full pin configuration map for the two sockets. It looks like with the updated pin map, we shouldn't expect any kind of compatibility with the older TR4 socket-based CPUs even if the sockets look visually identical.

AMD Ryzen Threadripper sTRX4 & TR4 Socket Pin Configuration Detailed - Different Electrical Changes Equal Zero Compatibility With Older Ryzen Threadripper CPUs

Since the start of the 3rd Gen Ryzen Threadripper processor rumors, we have been hearing that the new TRX40 platform won't support older processors. This was confirmed a few days ago with the announcement of 3rd Generation Ryzen Threadripper processors and the respective TRX40 series motherboards. Motherboard manufacturers clearly mentioned that their TRX40 series are compatible only with the 3rd Gen Threadripper series and not the older lineup.

Today, HwBattle has released the first pin layout of both the sTRX4 and the TR4 socket which shows just how much of a difference there is between the two sockets. Right from the start, we could not that on sTRX4, lots of pins that were previously unused by the TR4 socket have been enabled. The pin count is still 4094 for the socket itself for the SP3 socket but the revised naming should be considered here. The sTRX4 SP3 socket has more pins enabled than the TR4 SP3 socket.

The following are high-res photos of the sTRX4 and TR4 socket pin layout. (Image Credits: HwBattle).

AMD sTRX4 SP3 Socket For 3rd Gen Threadripper:

AMD TR4 SP3 Socket For 1st/2nd Gen Threadripper:

AMD Ryzen Threadripper Generation Comparison: