A green MVP in the tech support forums says
One thing I noticed with the reset was that “Triple Buffering” is set as enabled. I had mine set to disabled and this caught my eye. I did some experimenting. That setting jumped my total Ram usage by a good amount - around 500mb. Try disabling there.
Might be something for you to take a look at if you're still seeing problems in DX11L

Also for those like me who were waiting to switch, a blue poster in the tech support forums while discussing crashes similar to those here said
Looking into this it appears the crash is related to a DirectX12 issue our developers are actively looking into resolving via a future patch or hotfix.
Its coming soon, but it doesn't seem a good idea to keep using DX12 right now. IsBoxer can't help us with a bug in the game.