There are indeed clear differences between the species of dogs, but that is because those species have been artificially selected by humans. It's unnatural selection if you will. However, the differences between the dogs have to be seen in light of the different purposes for which they were bred. You cannot hold up a basset-hound and a collie and suggest one has the superior intellect by testing their ability to herd sheep or recognise smells. The system by which you derive the conclusion of 'intellect' must be robust enough to discount the individual differences caused by the selective breeding.

Human beings aren't selectively bred - so whilst I might agree there could be differences between the races, I don't think this can be down to 'intellect'. The culturally selective processes upon different races have led to different genetics - epicanthic folds in people from Asia for example but I don't believe there is a gene for 'intellect'.

What you've done is taken a given example (technical inventiveness) and suggested this is how we measure intellect. I would suggest this is like measuring groups of dogs on their ability to herd sheep. If you remove all the selection bias you have applied there will likely be a spread of intelligence across people in all races - but this intelligence will manifest differently in different places due to different cultural pressures.

In short, I think you've come to a biased conclusion of what constitutes intelligence or being intellectual. :o)