XFX HD-557X-ZHL2 Radeon HD 5570 Video Card - 1GB, DDR3, PCI-Express 2.1 (x16), DVI, HDMI, VGA, DirectX 11, Single-Slot

Not DDR2 as BB says

^ - Hard to say it appears from just Googling XFX HD-557X-ZHF2 to be DDR2, but with the full 128-Bit. That's what Egg has showed but now ss deactived; though MicroCenter confirms the -ZHF2 is DDR2.
http://www.newegg.com/Product/Product.aspx?Item=N82E16814150485
http://www.microcenter.com/single_product_results.phtml?product_id=0361418

The XFX site shows the -ZHL2 with DDR3 while only a 64-Bit, not that the XFX site details all the cut-back, gimped, winnies they polluted their product line with. There an orange arrow (second page/right side next to the P/N that appears to give the other(s) in the matrix, but doesn't have this -ZHF2.
http://xfxforce.com/en-us/Products/Graphics-Cards/ATI/ATI-Radeon-HD-5000-Series/ATI-Radeon-HD-5570.aspx