i have two 4870's in my system and i'm gaming like a madman - no problems whatsoever on my end. i've already done a couple four hour gaming marathons, too - and my ambient temperature is hot out here in Southern California. i have two Sapphire reference cards. i haven't touched the cooler, haven't tried to overclock, and haven't flashed the BIOS. my idle temps are extremely high in the mid-70's but they don't seem to get much hotter when i'm gaming. all i have is the GPU-Z graph and it doesn't look like the temp goes up much in-game. Everest doesn't work with them so i can't use that to monitor in real time.