Why this project runs extremely low?

Hi everyone 

I don't know why this project runs extremely low?

the clips are in 1920 x 1080 and the graphics are about 4,5 gb...My colleague said that from is Aplle computer everithing runs fine, but from my desktop pc it's all a lag, even in timeline, so it's difficult to edit the video 

I've already put the reproduction resolution at 1/4 but the timeline is costantly yellow... 

I'm working with a i7 12700, 32 gis of ream and a RTX 3070. Could it be the external hard disk that suks? It'a a Western Digital 5 terabite HD drive (a meachanic one)  

Thx!