LCP
Largest Contentful Paint
37.3s
Poor
Good: < 2.5s
Measures how long it takes for the main content to appear on screen
Optimize Critical Image Delivery
How to optimize en.saif.sjtu.edu.cn
Optimize Critical Image Delivery
High Impact+25 points estimated
Why It Matters
Images are causing 19.2 seconds of LCP delay and using oversized files that are 8.6MB larger than needed.
How to Fix
Convert all banner images to WebP format for 65% size reduction. Implement responsive images with proper srcset attributes matching display dimensions (720x343 instead of 2560x1219). Add fetchpriority='high' to the main banner image and ensure it's discoverable in initial HTML without JavaScript.
0Needs Improvement
What This Score Means
A score of 56 falls in the "Needs Improvement" range (50-89). While it is better than poor (0-49), you should aim for 90+ to provide an optimal user experience and maximize SEO benefits.
This site is slower than approximately 35% of similar sites. The main issues affecting performance are image optimization, JavaScript execution time, and layout stability.
Addressing these issues could improve your conversion rate by 15-20% and boost your search engine rankings.
Core Web Vitals Analysis
INP
Interaction to Next Paint
30ms
Good
Good: < 200ms
Measures how quickly the page responds to user interactions
CLS
Cumulative Layout Shift
0.12
Needs Improvement
Good: < 0.1
Measures visual stability - how much content shifts during page load
AI Performance Analysis
This website has poor performance with a score of 56/100, primarily due to extremely slow loading times. The biggest problem is the Largest Contentful Paint taking 37.3 seconds, caused by a massive 6.2-second resource load delay and oversized images that need optimization. The site is loading a 25MB payload including duplicate video files and uncompressed images, while also suffering from render-blocking CSS and JavaScript files that delay initial page rendering by 3.5 seconds. Optimizing images (which could save 8.6MB), implementing proper caching, and minifying JavaScript/CSS could dramatically improve performance and reduce the excessive load times that are severely impacting user experience.
Other Optimization Recommendations
Fix Layout Shift Issues
High Impact+15 points estimatedWhy It Matters:
Unsized media elements are causing 0.117 CLS score from images and videos loading without dimensions.
How to Fix:
Add explicit width and height attributes to all img and video elements, especially the banner video and carousel images. Use CSS aspect-ratio or padding-bottom technique to reserve space before content loads. Preload the banner video poster image to prevent layout jumps.
Eliminate Render Blocking Resources
High Impact+12 points estimatedWhy It Matters:
Font and CSS files are blocking first paint for 3.5 seconds, delaying all content visibility.
How to Fix:
Add preconnect link for cdn.campuswit.com in HTML head. Use font-display: swap for custom fonts to show fallback text immediately. Inline critical CSS for above-the-fold content and defer non-critical stylesheets with media='print' onload technique.
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Related Performance Analyses
More Generic Speed Tests
Generic Performance Resources
Remove Unused JavaScript Code
120 KiB of unused JavaScript increases bundle size and parsing time without providing functionality.
Optimize Image Delivery Strategy
Large, unoptimized images waste 303 KiB and lack proper dimensions causing layout shifts.
Eliminate Render-Blocking Resources
Render-blocking CSS and JavaScript delay LCP by 3.8 seconds, severely impacting page load performance.
Fix Layout Shift Issues
Unsized media elements are causing 0.117 CLS score from images and videos loading without dimensions.