Can Google.com and other heavily trafficked websites get a “fast” rank using Google's PSI API?

Question

Google changed its PSI definition of fast-ranking FCP from 90-percentile to 75-percentile below 1000ms

From PSI documentation:

Answer 1

Will a page like nytimes.com ever be considered fast with this standard, when even google.com's desktop page is ranked slow based on field data?

The answer is: YES, absolutely.

I get your confusion. It is caused by the false assumption that Google has a well-performing website. Please note that Googles homepage is ridiculously large. The HTML alone is over 200kb. The javascript it loads weighs a massive 436kb. The total weight of the page is over 1Mb. And what do we see on this page? Absolutely nothing. It is literally an empty white page. One megabyte is the amount of code that could fill 500 pages of a book. The code in these two Harry Potter novels needs to be executed by your browser as soon as you load this empty page.

Just to give you another idea of how rediculously large this is: I own a web development agency in Amsterdam and my website (front page) is just as emtpy as this Google page. However, it weighs only 41kb (including a completely unnecessary custom woff2 font file, which takes up 17kb).

When you connect to the Google homepage with a regular 3G connection, the page takes over 3.5 seconds to load. Just think about what that means for people in Jamaica or Cuba! They will have close to no access to Google on desktop, or at least a very bad experience. As a comparison: my website loads in 0.7 seconds over regular 3G. It is important to know that size is the main speed influencer when you have slow(er) internet (which is half of the world).

So... the Google homepage on desktop is a very bad example and more than deserves its low (speed) score. The New York Times can easily get a better score, simply by reducing the weight of its pages below the weight of the Google homepage.

Performance score versus FCP

Last time I checked (early Feb. 2018), the Desktop google.com received a 100 Lighthouse synthetic score, which is supposed to be interpreted as "there is little room for improvement," and yet, the page is ranked "slow" because the 90th percentile FCP is way over 3s.

In the part above you relate the score of 100 to the FCP. It is not as simple as that (anymore). The performance score is a complex metric. It is the weighted avarage of the variables below (note that the FCP is no longer part of this).

First meaningful paint - weight: 5
First interactive - weight: 5
Consistently interactive - weight: 5
Speed index metric - weight: 1
Estimated input latency - weight: 1

Note that the Google homepage takes 3.5 seconds to be interactive (according to Lighthouse). However, it currently still scores 97 on performance, due to the way the metric is calculated, which is at least remarkable. This confirms that the (near) 100 score can be a misleading figure.