Still hard freezing/crashing as of today's new build with DX11 enabled. I can't even send a report to Anet when this happens, as it doesn't generate the pop up box. Sometimes the game lasts a couple hours without freezing, but most of the time it's around 15 mins. When it does work, it's very smooth. We also had entire squad crashes in WvW last night and most of them didn't have DX11 enabled, not sure if related.