Renowned overclocker Der8auer has tried booting an 32-core/64-thread Epyc server processor in an Asus X399 Zenith Extreme motherboard for Threadripper, and partially succeeded. Does that mean that Epyc and Threadripper are essentially the same? Well, not really.
You may recall that Der8auer questioned how different Epyc and Threadripper really are when delidded a Threadripper 1950X in 2017 and found a similar structure to Epyc underneath. This led him and others to question if Threadripper was really an Epyc chip with two if its dies disabled.
It turned out that wasn't the case. AMD's senior product manager James Prior clarified things by explaining that the two so-called dummy dies found on Threadripper CPUs are "basically rocks" and cannot be enabled.
Fair enough, but can an Epyc processor boot in a Threadripper motherboard with a little modding? Perhaps.
Der8auer set about trying to get an Epyc CPU to boot in an X399 motherboard, first without any kind of modification. That attempt failed, with no standby power coming on. He surmised that an ID pin was preventing the CPU from booting, so he began trying to isolate the culprit by covering random sections of the chip with isolation tape. With different sections taped up, all he had to do was press down on the CPU in the socket to see if the surrounding LEDs on the motherboard would turn off, indicating a problem.
This allowed him to narrow down his search and he eventually found the correct ID pin that was preventing the CPU from booting. Once only that single ID pin was covered, the system showed standby power and tried to initialize the CPU.
Der8auer was ultimately able to get the system to partially boot. However, it failed each time at the memory initialization phase. This likely means that Epyc could in fact boot in a Threadripper motherboard with a special BIOS, and that the SP3 and TR4 sockets are identical.
This doesn't mean a whole lot in the grand scheme of things, but is interesting nonetheless. You can check out the attempt in the video below:
