Topic: What Audio Interface/Soundcard best for my system?

Basically I'm doing mostly mixing and mastering on this build setup. I do record vocals some time but I don't record any live instruments and use mostly synths and my own custom design samples.

My pc build specs
8gb ddr 4 ram
intel i7 6700k quad core processor
Samsung 256GB 950 Pro M.2 NVMe Internal SSD
thunderbolt 3 motherboard http://www.gigabyte.com/products/produc … id=5479#ov
running windows 10 and fl studio 12.2

What soundcard/audio-interface will ensure I get the best performance from my system?