I think someone could be looking at this with a bit of tunnel vision to believe that user posted in the wrong thread. They post about a product they purchased that cleans up dust which is what is being debated about how to keep it out of the PC.....well I'd say it could be argued, and well at that, that the best way to not get dust in the PC is to not have dust in the room/building the PC is in. so keep your spaces clean in other words as a good starting point. The connection is clear to me. So until we all can afford to build industrial level clean rooms for our PCs, we will have to resort to more obtainable methods lol
I have wood stove and stack at least 15 cords of wood in my basement every year. It is ABSOLUTELY FILTHY how much dust gets in the air due to this. I tend to get the best filters possible, so high MERV ratings, so when my furnace does run and circulate air around the house it doesn't deposit that into a room that needs to be kept much cleaner, like my computer room. That individual is taking the approach with a preemptive advantage by having one of those like roomba vacuums (or whatever they're called) run around. and that's not such a bad idea from my point of view. I've been known to take standing fans and box fans and take my furnace filters and attach them to those fans and let them rip down in the basement. yet another way to filter out all that dust. a bit ghetto or redneck engineering, but that's how I roll
as for negative or positive....I've always made intake slighter higher RPM than exhaust, should the system have the adjustment capability, so positive pressure