well i would say im probably a good person to answer this question lol...

you get YLOD from an overheat, so as long as your room's temperature is fairly comfortable, there shouldnt be any problems. however, in my case, the door to my room is always closed because i am paranoid about my cat throwing up on my electronics, so the temperature of my room can climb due to the heat given off from my 3 ps3s. so basically i just keep my window open and have a really strong fan pointed at all my ps3s when i am killstreaking. i used to leave them on for killstreaks overnight, but decided it was a waste of power because when i am not there to quick restart every 50k kills, or about every 3 hours, i will get the bsp map error, and then my ps3s will just be sitting around for the next 6 hours sucking up power for nothing until morning when i wake up to turn them off. so in short, have a fan blowing at your ps3 if you are at all worried, and just avoid using it if it is abnormally hot. every so often the ps3 hosting the killstreak will freeze, but not as a result of overheating. that is why i always host on a dier, it has probably saved me from around 300,000 lost kills. i would stay away from overnight killstreaks just because youll get the error before the night is halfway over, but as far as damaging your system you shouldnt worry.

O and by the way 7 is a SUPER SLOW timescale, i have mine set to 30.0

dont forget to thank

umm, no you didnt, you didnt even answer his full question, which was whether or not you can get YLOD. besides, your answer was incorrect because it is actually very unusual to freeze, you just get the bsp map error after a certain amount of kills