Features:
-Each temperature sensor corresponds to its own fan Blue LCD backlight display
-Fits in a 5.25" bay
-Has a 40mm fan for HDD cooling
-7 color rotations behind the dial, or just set in single color
-Support 4 fans (max. output 18W)
-Monitoring all 4 fans speed (RPM) and their componentsÂ’ temperature simultaneously
-Not all connections are required to operate
-Reduced energy consumption and fan noise for quieter work environment
-Designed for DIY applications, can also be used for RAID towers, servers, industrial PCs
So like I said, as it only has 1 dinky little fan, you're not going to get the results you wanted...
As 4W4K3 said, 80mm fans for his ram cooling, I use the active one with the 40mm fan on it to help move air around in there. For the hard drives I think adding an extra fan or two in your case would help, maybe relocating your drives also might be a wise decision.
*edit*
Ahh, I checked a couple reviews and found nothing of the sort, in history of any air drive cooler decreasing the temp beyond or at 20F. So I'm not sure where you're reading your stuff.. bs.com or what but here's a site that it trustworthy
http://www.hwextreme.com/reviews/coolers/coolermaster_cooldrive4/page5.shtml
I've gone to the trouble of finding the page in that review that has all the nice little pics. So you can't mistake something...