The asrock would be better for overclocking which is what you appear to want to do. Very popular board with good results and a good price.
Any particular reason you are wanting to water cool? A Hyper 212 EVO will give you all the cooling you need without having to worry about a pump breakdown.
The 7950 will only pull ~150w - that 750w psu is overkill IMO. Even if you plan to go xfire, 600-650w would be all you need.
You should not see any bottlenecks on either side.