Best RAM settings

Hey guys, advice needed.

Setup: R7 1700, B350 Tomahawk, Corsair LPX 3000MHz 2x8GB.

I was stuck at 2666MHz, now on the latest bios (v1.7) it boots at 2993Mhz

• 16-18-18-18-36, 2T
• 18-20-20-20-38, 1T

What should I choose?

Thanks.