Overclocking i7 6700k Asus z170 pro aura - Processor speed vs Benchmark score

[justikar]

I'm in the process of overclocking my new system (i7 6700k and an Asus Z170 pro aura) I'm using Asus realbench and Intel Extreme tuning utility for bench-marking and stress testing. Asus realbench scored:
stock settings at 102267
4.5ghz at 1.325v 128664
4.7ghz at 1.39v 114374
4.8ghz at 1.39v 36771

The Intel XTU benchmarks showed a similar pattern. Why is the score getting lower even with increased clock speeds?

PS XMP is enabled and i'm using water cooling

 

[popatim]

What are them temps at those clock speeds?
Don;t assume they are fine just because you are watercooling.

 

[justikar]

None of them went higher than 75