Rule of thumb for fans

[jreffy]

seal it up good and filter :p

honestly though, i think you do get better cooling with neg pressure because (i think) it ensures more proper airflow - if you have positive pressure, the hot air isn't necessarily leaving the case quickly, which could bork your components. or at least make them less efficient

Common sense forces me to agree with this. So I think your answer is negative cooling.

Just as it was already mentioned, this creates more suction on the intake fans, which will pull in more dust and particles. Make sure you have good filters for your intakes (as well as making them easy to clean/replace) and you should be golden.

[nil8]

The Coolermaster Centurion 5 is a good sleek case with onboard filters and sports 120mm fans. I would check it out of you need a medium quality midtower.

[simon275]

Rule of thumb for fans dont stick your thumb in one.

Pretty much 120mm fans are good. It really depends on how much heat there is which is prortional to how powerful your components are. This will determine fan speed and number of fans. So if you are running a core 2 duo and a 7900gt say just a standard modern system you will need an intake and a exhaust fan running at 12v for full speed.

I have found filters no matter what is says on the packet cut down airflow a lot. So you may need to go for a top blow hole fan sucking out hot rising air or maybe if you have a big tower case then you can fit another fan on the front or in normal cases a fan in the side panel blowing air over the VGA is good as well.

[nil8]

A good power supply with 2+ fans (90mm or above) can remove enough heat that a blowhole isn't necessary. Still not a bad idea to have one, just up to you really.

Filters will always cut down air flow, it's what they do. The more clogged they are the worse their airflow is as well, so maintain your filters.

[a.Bird]

Negative pressure has given me better cooling results, but it also accumulates more dust and debris.

Nothing a pressurized can of air can't take care of every few months. :p

[fragged]

This doesnt really make sence, if you made an airtight box, had one fan blowing inwards at 2000cfm, and another outwards at 1000cfm, wouldnt it just slow down/speed up one of the fans by the other ones push/pull pressure

I did year 10 physics, so i still have nfi tho...

[Illusion]

no case is air tight they all have vents and what have ya. se neg presure does make more sence. but i have to admit that i do use pos pressure in my box.

[javafiend]

So, would it stand to reason that since negative pressure pulls in more dust, would positive pressure help to keep dust out or am I just way off base?

[nil8]

No, positive pressure still has dust, it's just in different places.
With negative pressure you have a lot of dust on your cables, around your air entry points and on the bottom of the case.

With positive it's mostly around where the excess air leaves the case, so any opening in the case. It also collects around the entry points, as it will with all setups.

[b4i7]

haha...i had a friend that stuck his finger in a processor fan once....thinkin its"the same speed as a case fan" cut a big gash in his finger....