Page Load Slowness, Decoded: ADEM Waterfall Makes Performance Issues Obvious

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Author: Magnus Solberg

When a user reports "the app is slow," the first question is always where in the page load is the delay? Is it DNS? The server? Client-side rendering? Until now, answering that question required time-consuming manual analysis, stitching together data from multiple tools.

ADEM now extends its RUM capabilities with a Page Load Waterfall view for a precise performance breakdown, giving IT teams the exact data they need to isolate bottlenecks faster.

What the Page Load Performance View Delivers

Select any page transaction to open a single-page view that answers three questions at once:

• How fast was it? The overall page load time and Web Vital Metrics—Largest Contentful Paint (LCP), Time to First Byte (TTFB), and Cumulative Layout Shift (CLS)—each scored Good, Fair, or Poor.
• Where did time go? A waterfall breakdown of the four phases mapping directly to the class of bottleneck, each expandable to reveal sub-steps.:
  
  
  • PREPARE – Device-side delays before the browser starts the request (Queuing, Stalled).
  • CONNECT – Network connection setup (DNS Lookup, TCP Connect, SSL/TLS). 
  • RESPONSE – Server processing and content delivery (Waiting/TTFB, Content Download).
  • RENDER – Client-side browser work after HTML is received (DOM Processing, Page Load). 

• Why was it slow? When a user's experience score drops for a specific domain, ADEM automatically identifies whether the root cause is the endpoint device, the network path, or the application—each assessed independently using the same diagnostic framework—and recommends a remediation.

Fig 1: A single view surfaces Web Vitals metrics, the waterfall breakdown, and AI-powered Root Cause Analysis

 

Two Page Loads, Two Different Stories

To see the waterfall in action, here are two page loads from the same user in the same browsing session. One loads fine. The other doesn't. The difference is obvious at a glance.

 

The page that loaded fine

Fig 2: Salesforce loads in under a second. All metrics score Good. No root cause analysis needed.

Salesforce loads in 0.9 seconds. Every metric is green. The waterfall shows time spread evenly across connection setup and server response—nothing unusual. The Root Cause Analysis panel is empty because there’s nothing to diagnose. This is what normal looks like.

 

The page that didn’t 

Fig 3: A user loads tubitv.com. The waterfall shows the server consumed nearly all the load time, and ADEM pinpoints the cause.

A different user loads a web application, and it takes just over two seconds. That might sound acceptable—but LCP comes in at 3.14 seconds (Fair) and TTFB at 2.44 seconds (Poor). Something is off. The waterfall tells the story instantly: the RESPONSE phase consumed 96% of the total load time. The server took nearly two full seconds just to start sending data back. Connection setup, DNS, rendering? All negligible.

ADEM’s Root Cause Analysis confirms it: Server Response Time is the primary cause, with LAN jitter flagged as a contributing factor. The remediation is specific: work with the application owner to optimize server response times, and investigate the local network for jitter issues.

Without the waterfall, this looks like a vague “it’s a little slow” complaint. With it, IT knows the server is the bottleneck, the local network needs attention, and the user’s device is fine. Right answer, right team, no guesswork.

 

From “It’s Slow” to “Here’s Why”

One page loads in under a second—all green, nothing to investigate. Another takes two seconds, and the waterfall reveals the server consumed almost all of it while LAN jitter made it worse. Same tool, same view, two completely different stories told in seconds.

That’s the difference ADEM makes. No more bouncing between dashboards. No more guessing whether it’s the network, the server, or the device. The waterfall shows where, the RCA explains why, and IT can act immediately.

Page Load Performance is available today through the Browser-Based Real User Monitoring (RUM) extension:

• Prisma Access Browser: Built-in natively.
• Chrome or Microsoft Edge: Enabled through the ADEM RUM extension. 

Read the ADEM Tech Docs  to get started.