They are referring to the DDR3 version of the 6670 vs the DDR5 GT 440 which is only one spot removed on the chart.
Unless you are looking at a different chart than me, the HD 6670 is
3 tiers below the GT 440 GDDR5. And in the article, they are undeed comparing the DDR3 6670 to the DDR5 GT 440 as both
being best card for $65.