If there’s one man in the world who understands the science behind processor delidding, I’m pretty sure that man would be Roman ‘der8auer’ Hartung. As we all sit with baited breathe in anticipation of the new Threadripper CPUs from AMD, Roman has already enjoyed intimacy to the level of a thorough delidding session. In his latest video he talks in some detail for the first time about the design of the new TR4 socket (also known as Socket SP3r2) and relates his first adventure at delidding a Threadripper CPU.
At the moment no delidding tool exists for AMD Threadripper CPUs, which means that Roman was forced to rely on the tried and trusted razor blade method to rip the lid off his Threadripper CPU. In a similar fashion to previous delidding sessions with AMD Ryzen processors he started cutting around the edge of the heat spreader with a razor blade to dislodge the glue that joins PCB and IHS (integrated heat spreader). Then he attached a temperature measurement probe and started heating up the heat spreader using a hot air soldering station. He then inserted razor blades between PCB and IHS to apply enough pressure that the IHS would just pop off when the indium solder hit the right temperature, in theory about 160-170 degrees Celsius. Despite resorting to using two hot soldering stations to increase the heat to 180 degrees, the IHS refused to budge. Only by applying a lot of pressure to the IHS did it finally pop off.
The big surprise after removing the IHS was that it revealed not two Ryzen dies, but four. This is identical to AMD EPYC sever processors. Surely AMD wasn’t offering four octa-core processors on one PCB. To determine which CPU was active during operation, Roman drilled holes in the IHS so that temperature probes could be inserted above each die. This would give him a reasonable way to monitor the temps of each die and thus a way to determine which were active. Unfortunately once the chip was returned to its socket, it immediately died. Exactly why remains a mystery. AMD however have confirmed that two eight-cores dies are used, and two are not.
You can catch the full video from Roman here on the der8auer YouTube channel.