Heat output 250 saki's vs 400 radium

[SmartWrasse]

Obviously 400 > 250, but we keep hearing about how powerful the Iwasakis are. Would there be much difference in heat put into the water comparing 250 saki PFO vs 400 radium pfo HQI if bulbs are 10 -12 in above water and a shallow reef tank?

Thanks, Mike