Well, if you mean as a dust factor I keep my computer very clean and have a professional level anti-static dust vacuum/blower but the computer itself runs very efficiently already as is. For me it's more sort of an OCD thing. I want to build as efficiently as possible and I don't mean efficient for the money, even if I don't ever use as much PC power as I have. If I could I would 4-way SLI Titan Z's, but I've always been interested in a custom loop liquid cooler. That being said, as a professional IT technician, I know that I can achieve the same effect with closed loop liquid cooling that I can with a custom loop for way less hassle. So the real question then becomes, other than cosmetic effect, is there really anything more efficient about custom loop than closed?