>>195
https://html5test.com/ だと
Basilisk (Serpent) 55のスコアが1番で
Firefox 45.9.10が意外と侮れないと言う結果に

Firefox 62.0 (参考) 496
Basilisk 55 (20180828) 471
Basilisk 52 (20180908) 465
Firefox ESR 52.9 (参考) 462
Firefox 45.9.10 (20180828) 426
Palemoon 28.1.0a1 (20180908) 424
Mypal 28.0.1 423
Centaury 0.0.1 423
Palemoon 27.9.1a1 (20180825) 400
K-Meleon (20180825) 400