The Malays in Singapore is a very different breed from the past.
One of the reasons told to me is that their assimilation into the top-aided schools as well as inter-race marriage has led to the emergence of a very competitive breed of Malays.
One Malay i know owned more than one house.
Many Malays owned cars - take a look at weddings and you see the whole carpark filled.
They are much more confident, articulate and determined to fight for their rights and make their mark in the society.
They do very well academically, not just in PSLE but also in tertiary institutions. They are more hardworking and dedicated than the other races.
Of course, those in their religious schools are the elite and they received scholarships to the best universities in Saudi Arabia and others.
All in, their attitude are more akin to the original migrant. This is to the good of Singapore and testimony to the government's policies. Economically well off groups are good for Singapore.
Thus I am not surprised if the top student is a Malay. The PRC Chinese does not really count unless you belong to the ostrich mindset.