I’ve been getting this for ages now, without an SSD, i think it has to do with having the interp set itself (ie having it set to like cl_interp 0) but i could be talking bollocks as i have no idea what i’m talking about.

for me, switching to an account with a fresh tf2 install didn’t even play the demo smoothly, so i can’t verify if other people can watch your demos fine but yeah, i don’t think its the SSD’s fault, though it could be i guess.