In his latest webmaster video, Matt Cutts discusses page speed and if it is an important factor for mobile than for desktop.
The video is in response to question: "Is load speed a more important factor for mobile? Is it really something that can change your rankings, all the things being equal"?
Cutts decided to take the second part of the question first. He said, "We have said that we consider page speed in our rankings and if your site is really, really slow, it can rank lower. We should not talk about an absolute number of seconds because websites have different speed in different parts of the world as there's different bandwidth and speed in different parts. However, it is good to look at your neighborhood of websites. Look at the websites that are returned along with you and if you are the outlier. If you are at the bottom because your site is slow, the page speed might be affecting the ranking".
Matt Cutts also added, "What’s interesting is that factor applies across the board and is not specific to mobile. However, when you use your mobile phone, you do notice if the site's load time is reasonable. So, Google will continue to look at the ways that will help us in finding out how fast a site and the page speed of a particular page. We want users to be less frustrated, so it does make sense to incorporate speed into our rankings or more for mobile".Google's Matt Cuts on Importance of Page Speed for Mobile Sites!,