I think what you are seeing is asynchronous script behaviour.

Usually scripts are executed as they are found on a page, in order. But this causes problems if for example they are slow or have to download resources (or scripts) and block the rest of the page - causing even pages to partially render, creating a bad experience.

Asynchronous scripts will start executing after the page is rendered. This is good user experience because content will appear even if a script is blocking the rest.

I would say you have other stuff in your pages that is causing the DFP scripts to be late. If you have scripts for sharing on social networks try to move those to after the DFP scripts, just before closing the </BODY>. If you have analytics make sure you have only one - people don't need tracking number via three different services. Also analytics should be at the end to make sure they don't block anything important - better to lose one pagecount than an ad, right?

If you have to load resources (CSS, images) make sure these are cacheable. Also images should be of the correct size and have width and height specified (otherwise browsers will have to calculate these).

Every second counts when it comes to user experience - and realising revenue.

You can visit webpagetest.org and run a test on a page in your site to see where things get slow - or just use developer tools (F12 in most modern browsers) to see it.

My Adsense tags are asynchronous and they load up instantly.

Also my site loads up very quickly as well, which is where the problem comes in. The site loads up in full within a second, but the ads in the DFP locations do not come up for at least 2 seconds or even 4 seconds on some occasions.

So if a reader comes on and the site loads and he doesn't see any new headlines, he might log off before that ad ever renders or clicks to another page before the ad renders and so forth. So I lose the view and the potential ad click.

Sorry, I understood you had the old DFP tags and were replacing with new ones and that's when things started happening.

Check the webpagetest.org and see if you can pinpoint a specific slowdown.

I should note the DFP tags are not through the traditional method.

The network in question is giving me a header code and then ad snippets like this: <!-- ATF 300x250/300x600 Combo Tag: 300x600 300x250 --> <div id="home_XXXXXX"></div>

So maybe it's taking an extra second or two for the header code to speak with the snippet?

Their old method of DFP ad tags was not done in this manner.

Do you have any "googletag.defineSlot" and "googletag.cmd.push" calls?

If not, I think this network is providing you with their own tags.

No, they are providing me with their own tags, but they are using DFP to serve.

The old tags were theirs as well, but they were just hardcoded and there was no header tag that had to be placed. But there was some directive from Google where everyone on DFP had to change over to some new code so all of the tags had to get changed and now (at least this network) is using a header code with snippets instead of the simple 'place a tag here' method like adsense or any other network that I've worked with.