4.3 performance question

Hi all, so I stopped playing at 4.0 release, as did many due to the performance and bugs, however with recent videos on 4.3s performance being the best since sliced bread I jumped back in, I loaded up gigasctructures and ACOT being the 2 only large mods and cracked on, but by about 50 years in, my game is CHUGGING along, multi second days and of course the ususual month change lag, which is unavoidable but its REAL bad.

For reference im playing on a medium galaxy, 12 total empires plus myself.

From videos ive seen online, surely this isnt suppose to be as slow as it really is right?