200 watt is stock TDP, you can go lower if you undervolt and mod BIOS in your card, you can reach anything in 120-150 watt range depending on sillicon quality in the card.
After all mods, 7950/280 does 250-270 sol/s (clocked 950/1300-1400), 7970/280x does 280-300 sol/s (950/1450-1600), at least that's my Sapphires do.