It's not the drivers per se. After yesterday's Windows update FF40 blacklisted the driver for direct2d acceleration and WebGL. No idea how a Windows update lead to this but as of right now you can't enable h/w acceleration in FF40 on Win10 on 353.62 drivers. I've tried forcing it but that completely breaks FF rendering. What's funny is that the same FF40 (albeit it's beta but there are no changes) was working perfectly on the same drivers prior to yesterday. Gotta love these forced updates, eh? Some details.