WD Green and Red

Acoustic specs are exactly the same:

Green: http://www.wdc.com/wdproducts/library/SpecSheet/ENG/2879-771438.pdf
Red: http://www.wdc.com/wdproducts/library/SpecSheet/ENG/2879-771442.pdf

Don't use the Green drives.

WD won't warranty the Green drive for 6-bay NAS solutions. We've seen Green drives drop out of RAID often, so besides a 2-bay RAID1 configuration, go with the Red.

In that case, I won't consider the greens, thanks for your inputs

Got another question about WDC reds.

During my tests with 5 400GB Seagate Enterprise drives, the drives' temperature periodically rise over 45/46°C and the fan speeds up for a while till the temperature is back to normal. This happens when drives are idle too.
I was hoping the WDC Red drives were running a little cooler, in order to prevent the fan to speed up - at least when drives are idle.

Thanks

Yes, the WD Red drives (and the equivalent Seagate NAS drives) should run cooler than those old enterprise drives.

The datasheet for your old Seagate drives might still be available from the Seagate website; comparing it to the Red datasheet I linked above might give you specific information.

I have one Seagate ST31500341AS and five WD30EFRX in my pro-6. The Seagate temperature at the moment is 37°C. The WDC drive right next to the Seagate is running at 33°C, the others are running 27-29°C. Overall temperatures significantly dropped when I switched to the NAS drives. Seagate NAS drives use about the same power as the WDC, so they should also result in cooler temps.

Indeed the WD would be quieter and cooler

http://www.seagate.com/staticfiles/support/disc/manuals/NL35%20Series%20&%20BC%20ES%20Series/Barracuda%20ES.2%20Series/100468393h.pdf

Not sure how much. These Seagate are very noisy when seeking. It's not the noise itself, it's the vibration which is transmitted to the chassis. If you place the HDD on a soft surface they're quite. If they're inside a PC, you can hear them from the other room.

My pro is in the basement, so the noise is not a concern for me. Though my impression is that the fan noise masks the disk noise with my current configuation.

I have a WD1002FAEX in the PC I'm using now - its been very reliable, but I wouldn't get another one - much too noisy. Definitely good to check the dba specs before purchase!

I am testing 5 ST3500320NS and they often reach 46°C when idle, which I understand it's the temperature when the fan starts to rev up.

BTW, I don't like the fan management: the fan stays at min power until the drives reach 46°C. Then it speeds up and does not slow down till all drives are below 46°C. In the meantime, the fan manages to reach max speed. I'd rather have the fan to speed up slightly when the temperature slightly rise, so to prevent it from rising more. Can the way the fan is managed be changed with OS4?

In the future, if/when I have my own house, I'm planning to have a place for my NAS, but at the time being they're sitting by me! :)

Unfortunately there are no options to manage the fan speed.