XMP vs Manual OC

[cRsFisA]

What's best? Should I just use XMP or try to mess with memory timings to get better results? (if possible). And even then,is it going to be a big difference in performance?
Memory: Corsair Vengeance LPX Black 8GB DDR4 2400MHz CL14 Dual Channel Kit

[Fasauceome]

Manual is always better for the possibility of going outside the rated spec

[Lemtea]

XMP is just what the memory has been validated for out of the box so for the majority of cases speeds/timings can be improved with manual tweaking. I managed to get a 2x8gb DDR4 Vengeance LPX 2400mhz kit to 2933mhz with just a small voltage bump. If you are going to manually OC your memory make sure to stress test your memory using something like memtest as memory can often be borderline stable and only crash under certain conditions. 

[RGProductions]

I recommend against xmp. I cannot get my xmp profile for 2666 to boot with my ram, but with a manual overclock and still decent timings 3666 has been stable for me before