Question about safari on macs

I haven't seen this anywhere on the internet, so i'm wondering if theres something wrong with my mac. but on safari, when i speed/slow down a youtube video using the keyboard shortucts (shift + comma) or (shift + period) the video will slow down, but there will always be a noticible pause on the video as i'm using the shortcuts. i'm asking because i then tried on chrome (what i'm used to) and it worked perfectly. no pause,no delay or anything. I'm wondering if that is normal. considering i spent upto a grand on the laptop, i wouldn't have expected it to be a downgrade from my window laptop.

with chrome however, there is a delay/lag when i pinch to zoom in, i've seen this on the internet but there doens't appear to be any fixes for it. the pinch to zoom on safari works flawlessly thought, very fluid.

I'm wondering if anyone with a mac has had a similar problem, and if there are any workarounds for it. i'm also wondering if people AREN'T have the problem, and if it's just an issue with my mac.

thanks in advance