Which one is better, a brand new subdomain or a second-level directory with PR 4

[Vicky2885]

Hey, all SEOers! May I ask you a question about subdomain and second-level directory?

Our website is about software, so we write many posts about how to use this software solve problems, and then use these posts to get ranks (we don't use the page of software to get ranks). And all the posts we wrote are listed under the second-lever directory, just like: www.xxx.com/support/ . But at this moment our boss want to list all the posts to the subdomain like support.xxx.com. By the way, the second-level directory is a page with PR 4, and the subdomain is brand new, even it doesn't exist now. So here is my question: should we list all the posts to support.xxx.com? If we choose to do like this, this will effect the speed of Google index, and we will take more time to build links for XXX.com and support.XXX.com?

Any answer will be appreciated and thank you advance!

to get rank instead of ranking the page of product,

[Vicky2885]

I am not English speaker, so I just find that I should say subfolder instead of the second-level directory. lol.

[RyanPurkey]

Hi Vicky. Having them in a subfolder would be better for search. See: http://moz.com/blog/subdomains-vs-subfolders-rel-canonical-vs-301-how-to-structure-links-optimally-for-seo-whiteboard-friday. Rand did a great Whiteboard Friday on this very question which should help you out quite a bit.  Feel free to show it to your boss as well.  Cheers!

[Vicky2885]

Thank you for Ryan, I also read this post after posting my question, and also read another post about getting traffic dropping after moving blog from XXX.com/blog to blog.XXX.com. https://iwantmyname.com/blog/2015/01/seo-penalties-of-moving-our-blog-to-a-subdomain.html  And I will show our boss the disadvantage of moving support form subfolder to subdomain. Thank you!