Not a whole lot is known yet about SP5, Zen4, or where Intel will be when these AMD products are available. However, will (any) current AMD CPU's fit the SP5 motherboards / socket?
1 Answer
Short answer: No.
Long answer: No. SP5 will probably have more than 6000 pins, using LGA, while the current EPYC CPU socket has about 4000 LGA pins. The current Ryzen cpu is also not compatible, because it uses PGA. Only Threadripper is remaining then, which also has 'just' 4000 pins. Today's CPU's don't support enough pins, and I'm not even talking about DDR5, PCI-e Gen 5, ...
