The 13400's P cores get a 200MHz maximum turbo boost increase, up to 4.6GHz from the 4.4GHz of the 12400. It also gets an L3 cache increase to 20MB compared to the 18MB of the 12400. That's expected due to the inclusion of the E cores. DDR4 and DDR5 memory support remains the same, at 3200MHz and 4800MHz respectively, though you'd expect good quality XMP kits to run faster than that without any issue.
Cores : 10 ( 6+4 )
Threads : 16
Performance core base clock : 2.5GHz
Performance core max turbo clock : 4.6GHz
Efficiency core max clock : 3.3GHz
TDP (Base) : 65W