This PHILIPS MASTERCapsule is more efficient than the IKEA led fixture
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You can not really compare the naked lamp with complete fixture.
First in the fixture the halogen wouldneed the ballast, so the efficacy would drop by about 10% due to ballast losses.
But most important is the fixture efficiency (the ratio between the lumens going from the fixture to the lumens emited by the lamp itself): With many desk lamps this is barely 30% (dark screen,...), so 100lm/W lamp could yield only 30lm/W fixture.
But on the other hand the LED's beam pattern (half-sphere) should allow to build fixtures with way higher efficiencies, ~80% should be easy attainable...