Load performance from loading assets from a subdomain on a server vs fetch files locally

Is there performance difference between fetching resources/assets from a same origin subdomain vs fetching it locally? which one is faster

I have this subdomain on same origin/server where all my websites resides that act as a centralized location for all of my global assets .e.g

main.mywebsite.com

and I'm wondering if it does make any difference in loading performance against loading all assets/resources locally

e.g. load global css

main.mywebsite/assets/global.css

vs

mywebsite/assets/global.css

any ideas, help? assume CORS has been implemented already.