Technically it's not a metric for one-of rendering, but memory leaks by an open browser tab have bugged me a bit lately.
Safari does a per URL report in MacOS, and the ancient MacBook with "only" 8GB RAM gets a tad hot and bothered when a local PC store page runs up a 1.5 GB tab just sitting there, GMail snarfs 1 GB if not opened in a fresh tab once in a while, etc.
Technically it's not a metric for one-of rendering, but memory leaks by an open browser tab have bugged me a bit lately.
Safari does a per URL report in MacOS, and the ancient MacBook with "only" 8GB RAM gets a tad hot and bothered when a local PC store page runs up a 1.5 GB tab just sitting there, GMail snarfs 1 GB if not opened in a fresh tab once in a while, etc.