In the same environment from birth, randomly selected children from Germany and, say, the DRC will likely not have IQ scores too dissimilar by the time they're 18. This can be seen with children of different ancestries raised in military outposts having very similar IQs as adults.
I still think Germans are inherently smarter, but not enough to warrant a change in policy in regards to opportunities or, in characteristic German style, a full-blown genocide against the "lesser" folk.