We were able to measure the temperatures on each of the drives with our trusty RayTek Laser Temperature gun by simply pointing the laser at the top centre of each drive to get a reading. The temperatures for each drive were measured midway through our Sandra benchmarks; these being the last software tests we ran allowing us to achieve typical results. Room temperature was also consistent throughout the entire testing period at around 30c Celsius.
Surprisingly, even though the Raptor was spinning away at 10,000 revolutions per minute, it still didn't quite reach the 50c mark and was far from being too hot to the touch. Admittedly, testing was performed with the drives placed outside of a PC enclosure which helps to explain why each of them operated somewhat cooler than one would have expected. However, providing your case has half decent air flow (particularly over the hard drive bays) I think it's safe to say you've nothing to worry about in this department.
In terms of noise levels, I have to say I was struggling to hear anything coming from the Raptor at all, regardless of what tasks were being performed at the time.
The whirring sound of the 9800 XT's reference fan was enough to wash out anything audible coming from the drive. It was only when I put my ear up to the drive itself that I heard its inner workings ticking away. This also applies to the Seagate drives, although already renowned for being some of the quietest drives on the market, I have to say there honestly wasn't much in it between the Raptor and the Seagate drives. Evidently, the fluid bearing motor is playing a role here too (which the first Raptor drive lacked).
I'll also point out that when placed inside a case with several fans etc. this would only more so attribute to the overall quietness of the drive.
Find the lowest price on Western Digital Raptor WD740GD Hard Drive!