For publishers, Google’s AMP and Facebook’s Instant Articles are two different efforts with the same goal: creating a faster, cleaner mobile experience that can better attract and hold onto mobile readers. But a question since the inception of both products (February 2016 and May 2015, respectively) has been how much of the performance and engagement gains that Google and Facebook promised have publishers actually seen — and whether those gains have helped with revenue or overall reader retention.

Some new data from Chartbeat suggests the affirmative, on at least the performance and engagement fronts. Analyzing the mobile traffic data and reader behavior across the sites in its network, Chartbeat found that AMP pages load 4 times faster than standard mobile sites (1.4 seconds vs. 5.3 seconds). The performance of Instant Articles was even more impressive. According to Chartbeat, nearly 90 percent of Instant Articles load too quickly for the company to register a load time.

Overall, Chartbeat found that, as of May, publishers that adopted AMP got 16 percent of their mobile traffic from the pages, compared to 14.8 percent on Instant Articles. (Chartbeat also found that 97 percent of its publishers were using both formats.) Those numbers are a significant increase from when both formats were introduced, as the chart below shows.

Those performance gains seem to be having a real impact on reader behavior. Readers typically spend 48 seconds on a Google AMP page, longer than the 36 seconds they hang around the typical mobile site (though few publishers will be particularly inspired by either of those numbers). Chartbeat doesn’t have direct access to that engagement data on the Facebook Instant Articles side, which means we can’t draw direct comparisons here between the two efforts.

(It’s possible that the route mobile users take to AMP pages influences that time-spent number, though. Most AMP views come from Google search results — meaning the user has already expressed a level of interest high enough to type in some search terms, look through options, and pick one. That should create an engagement level higher than, say, seeing a link in a tweet or your News Feed.)

One difference can, however, be seen in the number of pages that are get traffic via Instant Articles and AMP. Chartbeat found that, on a typical day, three times as many of publishers’ AMP articles get traffic as their Instant Articles content. In other words, when it comes to the lifespan of content, AMP has a significant edge over Instant Articles. But that’s not exactly surprising, given that search lends itself better to long-tail, evergreen content than social platforms.

But questions remain about the true impact of the efforts on publishers’ audience and ad revenue. In its whitepaper, Chartbeat also points out that, while more publishers are testing AMP, “the number of articles posted by those who have been testing the platforms for some time has leveled off.” And a number of publishers have pulled their content from Instant Articles, citing disappointing revenues. While these efforts are fulfilling many of their technical promises, there’s still concern about just how sustainable they’ll be.