ok. now since they are similar in price and performance. but the warrenty on zotac 450 is for 5 years (3+2) and on powercolor 5750 is 2 years. so which to purchase ultimately. price of HD 5770 from sapphire is 20 dollars more. what u say.
the non OC gts450's are pretty slow, however, if you are into overclocking, you have much to gain. There are many well overclocked units around, getting close to 5770 performence, but will cost extra and then you may aswell get a 5770. The zotac is a non OC'd card i think. Probably best to stick to brands like asus, msi, gigabyte, sapphire, powercolour, xfx, even inno 3d are good for budget.