Sorry for polluting your thread, JackIT, but I've made 2 tests with 2 identical rigs that I want share.
I wanted to know if mem underclock (-502) would underperform mem 0 performance.
Results looks interesting.
Rigs have same mobo, cpu, ram, ssd, psu, risers and 6 x ASUS STRIX 1070TI.
Tests were done with Enemy 1.09b and last exactly 24 hours.
All cards are set: 70% Power limit (126W), 70C Temp Limit, Core Clock: +100

1. test:
RIG1: ASUS_L: Memory Clock: -502, 291.49613601 RVN
RIG2: ASUS_R: Memory Clock: 0,  293.82484280 RVN

After 1. test RIG2 with higher mem clock gets advantage of 0.007988, or less than 1%.

2. test:
RIG1: ASUS_L: Memory Clock: 0, 287.17642980 RVN
RIG2: ASUS_R: Memory Clock: -502, 295.71330164 RVN

Looks like RIG2 is even more faster with mem clock -502.
Advantage of 0.029727, or 2.97%.
RIG2 looks faster despite of identical hardware.

Conclusion: underclocking mem could gain you slightly better reward.