How long till a subdomain ranks?

I saw a lot of my competitors use subdomains to cover big niche relevant search terms, so I try to do the same now. How is a new subdomain viewed by Google? Is it treated like a new domain (sandbox time) or will it be able to rank faster than a completely new domain?

It has been 1 week now since I created it and I'm in the top 3 in yahoo.com for that keyword and on the 3rd page on bing.com. However I'm not even in the top 100 on Google.com

Anyone has some experience with this?

I ranked one PBN domain in one week,with the help of high quality link building and GSA.