I haven't pushed the memory on the card yet so should get some more out of that I could push the CPU more also but without a delid temps are fine at 4.9 but 5.0 needs a voltage bump and knocks on 90deg with synthetic tests.
My bad, I meant RAM at 4000mhz. Overclocking memory on the card is almost pointless. I would recommend a delid if temps are a concern as I did get quite a drop in temps, that said an extra 100mhz prob isn't worth holding your warranty for. I upgrade quite often so I don't usually care for warranty.