IgorsLAB published Sapphire HD 7750 Ultimate in review - fast passive card for the HTPC Retro 11 years ago A quote from the article:

It is no secret that cards with power dissipations below the 100-watt limit can already be cooled well passively. If you then move close to the 50 watt limit, things get really interesting. No matter if in a free setup or in a tight case, this small amount of waste heat should actually be manageable.

  Sapphire HD 7750 Ultimate in review - fast passive card for the HTPC Retro 11 years ago