What's the fastest Nvidia card that can be reasonably run with passive cooling provided by an Accelero or HR-03. Upright case, but airflow would best be described as moderate (silent PC bias). I would like to occasionally do some gaming, but gaming will probably account for no more than 1% of uptime. Mainly used for high definition video playback/recording. The motherboard is an asus x48 with intel quad core q9650. The main reason for going Nvidia would be for better integration with the pure video decoder. Otherwise I would go with an ATI HD4850. Any thoughts?