Also remember that the specified temperatures are just for the ambient air around them. The parts themselves are typically allowed to be hotter. It still looks like it's plenty cool enough in there, so as long as the power supply can handle a 7200 rpm drive then temperature shouldn't be a concern. So if you happen to have one lying around, you should be able to use it. If you're buying a new one just for the Roamio, I'd recommend a 5400/5900 rpm drive just to be extra cautious. But manufacturers are hiding which drives are low rpm. We know green and A/V drives are low rpm, but you can also compare the power consumption between different models to figure that out.