A quick glance at the spec sheet shows most of the key specifications remain unchanged, with the most substantial change being that the 12-core 3900XT comes with a 100 MHz higher boost, the 8-core Ryzen 7 3800X gains 200 MHz, and the 6-core Ryzen 5 3600XT gains 100 MHz.
Due to refinements to the 7nm node, AMD says it improved boost frequencies by 2-4%, but it also improved boost residency, or how long the processor remains at its boost frequency, by up to 80%.
Read more @ Tom’s Hardware