All of those video standards are designed from day 1 to be hardware accelerated, they have a completely fixed pipeline with no control branches, with very few d

All of those video standards are designed from day 1 to be hardware accelerated, they have a completely fixed pipeline with no control branches, with very few data dependencies (stuff like A+B=C C+A=D). JS/CSS/HTML5 are not, they essentially have an open ended and infinite amount of branching and data dependency and I'm very skeptical a card could achieve much. This is before we start talking about stuff like latency to the main CPU, CPUs are EXTREMELY fast in comparison to access to buses like ram, and especially PCI-E, I would not be the least bit surprised that even if some theoretical infinitely fast HTML5 accelerator card existed, it would still not be worth using due to latency of fetches from the card. It's already not worth offloading things like cryptography to accelerator cards, and every major crypto algorithm was designed to run fast in hardware. And this is before we start talking about stuff like AES-NI.