On 9/16/2014 13:29, m.roth at 5-cent.us wrote: > > Opinions on which slot to use? My opinion is that you should read "Hot Air Rises and Heat Sinks: Everything You Know About Cooling Electronics Is Wrong" by Tony Kordyban. It is quite readable, for all that it is a serious EE book. Thermal dynamics is not a matter of opinion. Either someone is giving you a guess, in which case you have to decide if they're likely to do better than chance, or they have done the experiment or thermal modeling, in which case they aren't offering either a guess or an opinion. You could just assume Dell has already worked through the thermal dynamics and has provided enough cooling headroom that both slots can be used with hot cards. If you've found that they don't fight you on warranty replacements for cooked mobos or third-party cards, go ahead and take a guess. Or, you can do the experiment yourself. You have the equipment, you have the environment, and you have lm_sensors. Try it both ways, and let us know what you find. When your boss asks you why you are faffing about with R, tell him it's For Science! You do research there, right? Here you are, doing research, and you didn't even have to get a grant to do it. There's your science in the public interest, Mr Bossman!