AVCHD and Premiere Pro CS6

To be honest I have Windows 7, & CS6 with i7 CPU 16GB Ram but no Cuda card. I fill up the timeline with .MTS AVCHD footage and I have no problem whizzing up and down the timeline without effort. I can drop dissolves 'n' things on the clips and although they are red and need rendering, they still fly with little effort and will play back in real time. However, I have another PC with Windows 10, Prem CC 2018, an i7, 16gb Ram and a GTX Cuda Card. I drop the same footage on the timeline and it struggles and drops frames like nobody's business! No Red line just Yellow. I have spoken with the Muppets at Adobe who tell me it shouldn't play back in real time?

I know this doesnt help with your problem but would advise maybe upgrade your CPU only! I am sorry I ever advanced from CS6 as I have had nothing but trouble. Adobe even allow you to pay them each month, as long as you do not need any help with anything. Save any monthly outgoings and upgrade CPU, it will work fine.

you can't.

.m2t is mpeg 2.

.mts is mpeg4 or about twice as hard to decode natively.

you need either a faster cpu or transcode to a less compressed codec to play smoothly, dnxhd,cineform etc.