I've just come back to play Cities after a long while away and I noticed that I'm getting a stutter in the sim. I thought maybe an old mod (HDD's like a dusty attic) was being an arse and through clean installing then adding mods progressively it seems when I enable 81Ts every 20 seconds or so the sim freezes for a beat - less than a second.

I started a new city, let the sim run and just watched the traffic on highway and it was still stuttering even without building anything to develop.

Other mods installed: TMPE11, Precision Engineering, Imp Public Trans 2, Move It, Unified UI, Surface Painter, Skyve, Patch Loader, Node Controller Renewal, NetEx2, Game Anarchy and Loading Screen (all as up to date as possible).

I'm sure I never had this issue before and that was before I built this new PC!