This comes from experience. A dusty case will kill your hardware. Earlier today, i booted my computer to find an alarming idle temp of 60C! "That's not right, it gets hot, but not that bad" I told myself. I turned it off and opened my case, there wasn't really that much dust. I cleaned out the fan filters, which i then found to be caked in dust. I then took a can of pressurised air to my cpu cooler, stock intel. All clean, i booted up my computer after shutting the case. It idled at a respectively cool 40C. Dusting my case off just got cut 20C off of my temps. While dusty, the cpu on load went OVER the TJ Max, the maximum temperature it should operate. 90C. It now loads at about 70C. I know my computers, but i have a low budget. I can#t see a problem for expensive cases. IF you have a cheap case, be careful of your dust, it might cost you your hardware!
I have a waterblock on CPU and one on each of my 560Ti's. I have temp monitor software in windows and can set speedfan to shutdown the computer within 5 seconds if a temp goes over a certain level or the water pump stops working.
That helps us how? Yeah: Dust has surprised many a component of Mine. My previous GTS250 was always a bit crap, but dust had the idle temps on it at sixty. Motto of the day: remember to clean stuff out!
I think it's more important not to life filthy as heck Nah just kidding, I've been using my beige dream sidepanel-less for a couple of months now and the sight of that Noctua NH-C14 with all the dust simply disgusts me. I guess I just take it as an experiment EDIT: and oh not always is it the dust. I remember my dad whining about his computer crashing all the time and I was pretty sure it was full of dust. FALSE! It turned out that the main problem was that the entire NB-heatsink had fallen off.
Or have a filtered case This is a good horror gallery for you http://www.theregister.co.uk/2010/11/26/ventblockers_2/
Meh filtered - non filtered, the main difference is that you need to remember to clean those filters more often than the whole setup... Sure, it's more convenient, but if you forget, the result is the same.
Well from having to open up the case to clean inside to hoovering the filters every week when I do the rest of the house I'll stick to a filtered case.