This is a Chromium Issue related to Fonts. Google claims the fix will go out in July.
https://bugs.chromium.org/p/chromium/issues/detail?id=619981

Opera is a Chromium based browser. Same issue is with Brave & Vivaldi which are also Chromium based. Safari & Firefox both work perfect for some reason. Safari lags slightly though on certain sites while Firefox seems faster than on El Capitan.