http://www.guru3d.com/article/geforce-gt-220-review-test/3
http://www.guru3d.com/article/radeon-hd-5570-review/6
http://www.guru3d.com/article/msi-geforce-gt-240-review-test/5
http://www.pcgameshardware.com/aid,697132/Geforce-GT-220-reviewed-Nvidias-DX101-graphics-card/Reviews/?page=12
http://www.xbitlabs.com/articles/video/display/radeon-hd5670-hd5570-hd5450_6.html
In contrast to the others, this one favors the 220/240, but just barely.
http://www.legionhardware.com/articles_pages/ati_radeon_hd_5570,8.html
I think there's a pretty big difference between "minimum" and "recommended", too. ATi never states a minimum, just a recommended.
"Parliamentary inquiry, Mr. Chairman - do we have to call the Gentleman a gentleman if he's not one?"