I'll try to be short, I have a Gigabyte Setto 1000 case, and in it there's AMD 955 BE C2 - which idles at 35-40 C during these hot days (over 30 C in shade) and the main reason for heating: Sapphire Vapor-X HD4890 (which idles at 60 C).
Now I'm well aware that I have to improve my case airflow and will do same by drilling one hole in the lower right part of the side panel in order to place a 120mm fan to blow on the hard drives, and another fan will be installed on top (time for the handyman). Replacing a rear exhaust fan is also being considered.
For now, I have 2 x WD 640GB Caviar Black, and they are running at the temps of 40-45C, sometimes even reaching 50C when I'm gaming.
I know that operational limit for the HDDs is 5-55 C, but I'd like to see a general opinion are these temps too high and will they affect the HDDs in the long run?
35-40C is a perfectly reasonable temperature for a hard drive, especially if the ambient temperature is 30C or more. You really wouldn't want them to run any cooler than that. The Google study on disk failures found that failure rates actually rise as the temperatures drop from around that level - see: http://static.googleusercontent.com/external_content/un...
I have checked the Google study on the HDD failures and their connection with temperature. However, even now with a side panel open, the primary disk is at 42C and the backup one at 39. During a half-hour gameplay of Prototype, the temps went up to 47C.
Is there anything that can be done other than a) to place additional fan to blow on the disks and b) to install a small ventilator directly on top or below HDD? The disks are separated by 2 empty 3,5" slots.
If you look at the temperature vs. failure graph on page 6 of the study, you'll see that the very lowest failure rates are from about 37-46C, and the rates beyond that aren't a whole lot higher. So I really don't think you're in a position where you have to worry.
That having been said, it might help if you move the drives a little closer together and put in a baffle (cardboard, perhaps) so that the air can only flow right past the top and bottom of the drives. A smaller opening means faster airflow, as long as all of the air is forced through the opening.