It depends are you planning on enabling high resolution pack ?
If so then objects need to be set at ultra ,can't remember if extreme works too ,but below that
displacement mapping doesn't work , it's just flat texture.
I don't now about other DX11 features. (didn't test it out yet)
And why would you say now that you only gonna set it to very high?
I think you should test if higher settings will work too.
maybe not all ultra but at least maybe objects for above reason and the rest can be set
lower.
Your call.
Also which cpu do you have?
And which driver are you using for your videocard.
Current out is : 280.26 Whql certified
It increases performance with crysis 2