Performance of FPGA vs FPGA with SOC

The SoCs have the same fabric as the non-SoC counterparts, the only difference is some of the FPGA resources are replaced with a system on chip a hard silicon processor block implementation. Some algorithms belong in dedicated hardware and some fit well into a standard processing system. For example if I had a dataplane application I would probably keep that in FPGA logic, but if there was a lot of initialization, control, analytics, etc... you can often use a processor for stuff like that and that's where the SoC devices would be appropriate since you can use the same die for both parts of the product.