How Does a CDN Improve Performance & Page Speed?

No one likes a slow site. Most visitors will click away if a page isn’t loading fast enough, and Google actually gives sites lower search engine rankings if they don’t load quickly.

Luckily, there are multiple ways you can improve your site’s speed. Images and videos are the biggest culprits when it comes to slowing down a site, but they can be forced to load faster by using something called a content delivery network (or CDN).

Let’s explore the CDN basics, and how you can use the CDNs that Jetpack provides to speed up your images, your videos, and ultimately your entire site.

How CDNs work

A CDN is a group of servers distributed throughout different locations that provide content to your visitors as quickly as possible.

Most websites are hosted on a server in a single physical location. When a person visits a site, the text, images, and video all come from the same place.

Think of it as three people — we’ll call them Ted, Irene, and Vern — who each have signs that, when held up together, form a complete message. Now, imagine that these three people need to arrive at a plaza and hold up their signs at the exact same time. The only problem is that Ted, Irene, and Vern all live in the same building. When they rush out the front door at the exact same time, they bump into each other in the doorway and slow each other down.

When a single server is tasked with fetching content for a website, it’s all sent out the same “door.” But CDNs spread out those resources by housing the text, images, and videos in different places. Instead of Ted, Irene, and Vern trying to squeeze out the same front door, a CDN reroutes them from three different buildings. They can leave their buildings freely and arrive at the plaza to display their message quickly.

Location is another issue. The message is displayed faster if our sign holders are located in buildings near the plaza. But when it comes to content online, you never know where your message will need to be displayed — in the same country, or in one far away from your server.

That’s why CDNs make duplicate versions of your content and place them in servers located all over the world. This shortens the amount of time it takes for your site to load, even if the person viewing it lives on the other side of the globe.

A comparison of typical file delivery methods vs. CDN. Image from Wikipedia (CC BY-SA 3.0), courtesy of Privacy Canada.

Now that you understand the importance of a CDN, how do you get one? The good news is that you don’t need to do any technical work, because Jetpack offers CDN capabilities with the click of a button.

Speed up your pages with an image CDN

Images are big. A single image can use the same amount of bandwidth as several pages of text. The larger your images are, the longer it’ll take your pages to load.

WordPress will resize large images for you, but the file sizes may still cause long load times for your visitors — especially those on slower connections or mobile devices. So we recommend using the free WordPress CDN built into Jetpack.

Photon automatically copies your images to servers around the world. Whenever one of your pages needs to deliver an image to the user, Jetpack grabs it from the closest server. It handles things like replicating the image, storing different sizes of the image, and scaling the image displayed to fit the user’s device.

Photon, like any CDN, makes your site remarkably fast, and more enjoyable for visitors to use. And because it’s built to work with WordPress, you can rest easy knowing it’ll deliver the best experience possible for your visitors.

Videos can slow things down, too — and CDNs speed them back up again

While images may be large, videos are downright huge. Even a short video will typically be 30-40 times larger than an image.

Using a host that specializes in video distribution is one quick way to cut down on load times. Vimeo and YouTube are great options for free video hosting, and both have native support in WordPress. Paste a video URL directly into a page or post, and the video will magically appear on your site. These videos are served from a high-performance server with lots of bandwidth, and will load faster than they would coming from your web host.

However, the downside to services like Vimeo and YouTube is that they pay for their bandwidth with ads or links to other videos. You have no control over the content of “suggested” videos, and they often don’t reflect well on your brand or message.

If you want more control over what’s displayed on your site, and are concerned about speed, you’re in luck: for Premium and Professional customers, Jetpack offers a video hosting service that uses the same content delivery network as Photon, giving you on-brand videos with no slowdown to your site.

This allows you to simply upload video to the WordPress media library. Once uploaded, the video will automatically be copied to the our servers. Just embed your videos on any page to display them, and we’ll serve them without any watermarks, ads, or other distractions. You just get clean, fast videos that your visitors will love.

Here’s a test video to try out — how quickly does it load for you? (Try refreshing the page a few times or viewing this post from a different device!)

With Jetpack, you’ll get the benefits of enterprise grade video hosting platforms without distracting ads or “recommended” videos. If your site has a lot of video, upgrade to a Premium or Professional plan today to try this feature out!

To keep your visitors around for longer, speed up your site with CDNs

A fast site is necessary if you want a lot of visitors and to keep the good search engine rankings you’ve earned. While photos and videos — the kind of content that really engages audiences — can slow down your site, CDNs can help you speed it back up again.

Jetpack’s built-in image and video CDNs offer simple ways to improve site time with little effort required on your end. Try them out today and see just how fast your site can go!

What do you think of CDNs? Have any tips for using them well? Let us know in the comments below.

Lance Cleveland

Dad. Explorer. Rum Lover. Code Geek. Not necessarily in that order. Create of Store Locator Plus, the "enter your zip code, find the locations" map solution for WordPress.