Latency can vary widely. It can range
from as little as 34ms for LTE to 350
ms or more for 3G. Mobile latency is
consistent only in its inconsistency,
even when measured at the same location. This is due to a number of variables beyond the amount of data passing through the tower. Factors such as
the weather, and even the direction
the user is facing, can have a significant impact.
Download speeds can also experience
huge variance. The speeds can range
from a mere 1Mbps over 3G to as much
as 31Mbps over LTE. It is interesting to
compare this to the average U.S. broadband speed of 15Mbps, and to note
that 3G can be up to 15 times slower
than broadband, while LTE can be up
to twice as fast.
M.Sites are not a Cure-All for Mobile
Performance Pains. Many site owners
attempt to respond to the combination of high user demands, large Web
pages, and poor connection speeds by
developing smaller, faster, stripped-down m.sites; however, these attempts
are not completely effective, as up to
35% of mobile users will choose to view
the full site when given the option.
These full-site visitors are significantly more likely to spend than
m.site visitors. One study found that
for every $7.00 of mobile-generated
revenue, $5.50 was generated via full
site. Only $1.00 came via m.site, and
$0.50 via app. 9
Addressing the Problem. The chief
strategies for improving site performance have not changed as usage has
migrated from the desktop to mobile
phones and tablets, although a few
new tactics have emerged.
Only 20% of the time required to
display a typical Web page, whether in
a desktop or mobile browser, is consumed by loading the page’s HTML.
The remaining 80% is spent loading
the additional resources needed to render the page—including style sheets,
script files, and images—and performing client-side processing.
The three main strategies for improving performance are:
˲ Reducing the number of HTTP requests required to fetch the resources
for each page.
˲ Reducing the size of the payload
needed to fulfill each request.
˲Optimizing client-side process-
ing priorities and script execution ef-
The biggest drain on performance is
usually the need to complete dozens
of network round-trips to retrieve resources such as style sheets, scripts,
and images. This is especially true with
the relatively low bandwidth and high
latency of mobile connections. CDNs
(content delivery networks) can help
a bit by bringing content geographically closer to users, but the number
of requests has a much greater impact
on page-load times than the distances
those requests travel. In addition, recent findings suggest CDNs have limited effectiveness for mobile users. 3
Here, I discuss several approaches
to minimizing HTTP requests.
Consolidate Resources. By now it
is standard practice for developers to
styles into common files that can be
shared across multiple pages. This
technique simplifies code maintenance and improves the efficiency of
same script is not downloaded multiple
times for one page. Redundant script
downloads are especially likely when
large teams or multiple teams collabo-
rate on page development. It might sur-
prise you how often this occurs.