if you tell 200w, someone will come and tell it is not accurate, someone else will tell that it is 75 watts and 150 from the 8 pin, that is 225, others will tell you that reviewers with a oscilloscope measured 200 with spikes to 240
to be sure, up to 250 overclocked
ideally less than 200 watts
you can't please everyone, but you can be ready for most situations by just buying a moderated size psu with enough watts for now and for the future