I've read than in 2014, Google will reward HTTPS sites in ranking.In the other hand, I have also read that HTTPS is slower than HTTP.So, in my site, I just have a few HTTPS pages, so my question is: Should I put all my site in HTTPS, or just the few pages I need?
HTTPS vs HTTP for SEO
seo;https
It's a myth that HTTPS is slower than HTTP. Yes, your site may be a little bit slower but this can be prevented. Please check out this article for suggestions.From SEO perspective, it's definitely better to use HTTPS. As you've already said, Google will reward sites using HTTPS. You might want to read the official blog article from Google for more information about this.