No need for ventilation if you have good Air Pressure, Fan orientation and filter
Ummm, that's all part of ventilation. If you don't have intake vents to allow cool air in, and exhaust vents to allow heated air out, you have no ventilation. No ventilation equals heat build up. Never good. So of course you need ventilation.
And for the record, pressure comes from restricted air "flow" - either more cool air is trying to get in than can get out (positive pressure), or more heated air is trying to get out than can be replaced by cool air coming in (a vacuum or negative pressure). Too much of either is no good and negative is rarely ever desired.
If you can only have flow "or" pressure, flow is better than pressure.
Ideally,
reasonably "balanced" air pressure is really the goal. That is, a "little" positive pressure is good
IF you have air filters behind your intake fans. Thus you want a little (and a little goes a long way) more intake coming through your filters than total exhaust.That helps prevent dusty air from being drawn in through other cracks and openings in the case. Too much intake, however, causes too much positive pressure and that restricts the flow and causes heat to build up because the heated air cannot get out fast enough.
