gts450

Hi guys... I'm planing to buy GeForce GTS450... but I don't know which one... the GeForce GTS450 1024 MB GDDR5, or GeForce GTS450 2048 MB DDR3. I've searched Google and I haven't found something about GTS450 2048 MB. All I know is that GTS450 1024 MB GDDR5 (1804 MHz Memory Clock) is faster than...