Please help me.

Hi, this guy I know gave me a Nvidia Geforce GTS 250 1GB for free, I currently have a 8500GT in my computer. I dont want to waste my time and put the nvidia geforce gts 250 in my computer and find out its worst than the 8500gt so should i put the gts 250 in my computer it just sitting on my computer Im a gamer and 8500gt isnt working well i can barely play games. So should i put the gts 250 in or will it be a waste of time? Iv notced the nvidia geforce gts 250's heatsink and fan is 4 times bigger than the 8500gt's but which one is a better performer it will take me 5 mins to put it in but i just dont wanna have to waste my time so which is better?