Good Notebook very bad Resolve usability

Hi, I hope this is the right place for my issue.
I have a Dell Inspiron 15 9750 with the following fetures:
CPU i7-9750H 6+6 cores
32 GB ram
GTX 1650 4GB
M.2 512 GB
M.2 1TB

As you can see it is not a super powerful pc but still it is a very good notebook.
I mean, such a computer should be able to handle just one 4k video 15 mins long shoot with a sony 6400, right? Instead it is super laggy. I can't move freely along the timeline without experiencing latency, hiccup, image and audio freezing...

While this is happening my system runs like this:
CPU AVG 50%
Integrated GPU AVG 20%
GTX 1650 AVG 10%

So there is no thermal throttling whatsoever.

How could this be possible? I can expect this if I have maybe 10 4k videos in a pretty complicated timeline...but just one video? I can belive it...

1x h264 UHD is enough to kill your CPU. It's at 50% means all real cores are saturated.

If you had Studio version then h264 decoding would be done on GPU and all should be smooth. Free version uses always CPU on PC and it's always a problem. It's not only for you, but people with even more powerful machines. Laptops are another layer of problems- quite often they slow down a lot and have latency issue etc.

Use optimised media, which means waiting for transcode to easy to play format (Cineform, DNxHR etc), but then all will be very smooth.