In the newest update EA added these files to The Sims 4 on Windows:
TS4_x64_fpb.exe
Simulation_x64_fpb.dll
There are no in-game options to use this exe but you can force it by adding -fpb
to the launch options. You can find them in game properties on EA app and Steam.
I haven't tested the performance. The only difference I noticed is that the "FPB" executable can't use DirectX 9. The option either disappears or is greyed out, with a tooltip that says "DirectX 9 is not supported in Memory Boost mode. To access this option, deactivate Memory Boost."
As far as I know this is the only mention of "memory boost" in game but I might've missed a text line.