Which is better option or there is no difference in terms of speed or other issues like SEO, Backlinks
href="http://www.example.com/contact"
href="../../contact"
From what i observe, Absolute paths uses paths from left to right finally move to rightmost position as in http//www.example/contact
fpr relative paths: first it gets the current location, then based ../../contact or ../blog/articles move there.
Technically which is faster, as mentioned in answers speed difference is ignorable/minute. But how it works
There is no (measurable) difference in speed or anything as regards to search engines and other software that processes HTML pages as delivered on the web.
The reason is that relative URLs are resolved to absolute URLs applying well-defined algorithms that are known to authors of relevant software. So when your page contains href="../../contact", it will be resolved using the current base URL, and the nanoseconds required for this are ignorable.
The use of relative vs. absolute URLs from the authoring point is a different issue, and well covered in the question already mentioned: Absolute vs relative URLs