Usually, 55 is from RAM, so check the latencies, if you set them manually. Or increase RAM voltage a bit. Also you can try increasing the VCCIO and/or VCCSA voltage.
@autisticchris overclocking is about finding the best way to get the best score ;)
@bigblock990 i've tried AMD's first, but got me 1min 09 sec at 5.4G. Then tried Intel and here we go :)