Curious how much the 5450 loses to 4550, they are near identical cards except for DDR2 vs DDR3. One would think at the low-end bandwidth wouldn't play that big a part.
Bandwidth matters allot more on the low end then anywhere else, since the bitrate is often 64 bit, you get all kinds of werid combos of bitrate and ram types, basically if youu want something more then a glorified frame buffer never go below 128-bit GRRD3, GDDR5 would be even better since it's quad pumped you have near the effective bandwidth of 256 bit GDDR3.
But yeah, almost universally low end cards gain more from a bandwidth increase then they do from a GPU core clock increase, the reason is something has to feed the GPU. On higher end chips theres often so much bandwith that OCing the ram gets you nothing, just as is seen in traditional desktops. The same is not true for AMD's Fusion APUs, where the GPU shares the memory bus with the CPU, but has so much extra grunt that the memory bandwidth holds it back in a big way if you pair it up with slow bargain basement ram.