页面打开时间php发布\ get \ get来自浏览器

using Web Api to alibaba..

1. curl open page about 2-3 sec (try from different hosts)

2. php post file_get_contents open page about 2-3 sec (try from different hosts)

3. php get file_get_contents open page about 2-3 sec (try from different hosts)

Open Api from Web browser get answer immediately without delay.Why?